Absolutely! But before considering how they were considered artistic or the work of an artesian, it is worth considering (and rather dissolving) the dichotomy you've presented here between maps as 'strictly practical' and maps as 'art'. Bracketing the discussion of whether we can discuss 'art' as some sort of pure category devoid of other 'practical' functions in the premodern world, for the case of maps in particular, we can't really make this sort of distinction in the first place since, prior to the lithograph, there was no means of mass producing technical diagrams. As such, all even vaguely detailed maps prior to ~1796 are the individual production of one or more artisans. Furthermore, insofar as we can categorise maps into categories like 'practical' and 'decorative', their contents of these maps consistently belies a simple distinction. Paradigm examples of 'practical' maps in the middle ages, such as the portolan charts, frequently see inclusion of decorative elements such as elaborate wind roses, pictorial depictions of exotic places, coats of arms and so on (cf. decorative elements in early modern ptolemaic maps); and, while I take the converse to be less controversial here, even paradigmatically 'decorative' maps, like the large wall maps in Churches, were used for practical functions in the education of the laity or as props in sermons. So even insofar as might argue that something like the Carte Pisane is 'entirely practical' on some narrow definition of practicality, insofar as it is, it is an exception to the more general principle here that most all premodern cartography is in different ways both practical and decorative.

But back to the question at hand, we have a fascinating illustration of the decorative function of the medieval mappa mundi in a massive poetic description of the chambers of Countess Adela of Blois (a daughter of William the Conqueror) by Baudri of Bourgueil (or Baldric of Dol or even sometimes a different combination of those names...). Baudri, who was born ~1046 in Bourgueil in the Loire valley, was probably one of the foremost Latin poets in the French world and from 1107 to his death in 1130 Archbishop of Dol. At 1368 lines in Elegaic Couplets, the Adelae Comitissae (To Countess Adela; normally dated to 1099-1102) is Baudri's longest and most elaborate surviving poetic work.

The poem is presented as a fictive 'tour' of the Countesses's private chambers. This is highlighted in the opening couplet (unless otherwise noted all english quotations are from Monica Otter's translation [1]):

Go, little poem, to see a display of matchless adventures;

Enter the private rooms kings and counts call their own. (ll. 1-2)

After some introductory flattery the poet is allowed to enter her private chambers:

Trying to catch a few of her words, I move a bit closer

To her and quickly slip into her private room.

For, prescient as it were, she has told her servants about me:

Therefore without delay I am allowed to go in. (ll. 89-92)

And this provides the introduction to the main body of the poem, an extended description of the furnishings of these chambers:

I confess I was stunned at first, standing there on the threshold:

That bedchamber seemed to me like the Elysian fields.

For the chamber was decked with a tapestry, recently fashioned,

Precious the stuff it was made of, precious the workmanship. (ll.93-6)

Most of the scholarly attention to the body of the work has related to the long description of a tapestry depicting William's conquest of England and the battle of Hastings (ll.227-566), which may well be (at least based on) the Bayeux tapestry -- there is nothing to allow a definitive judgement though and the poem itself suggests that its description is fictive ("I have rather sung what ought to be, than what is", l.1354). After this description of the tapestries on the walls, Baudri moves to describe the decoration on the floor and ceiling:

Finally, who could describe the chamber, do proper justice

To the ceiling, the floor - who could describe it all? (ll.573-4)

It is here that this comes back to the present thread, since the ceiling and floor are covered with a map of the heavens (ll. 583-718) and earth (ll. 719-946; literally a mundi ... mappa l.723) respectively. The former depiction of the heavens is described as a work of great artistic skill (sic studium ... artificis l.586) which appears to show the stars moving although it is a static image. But the floor is presented as the greater poetic challenge (incidentally, this is also the only portion of this poem that we find later excerpted to be included in a 14th century geographical miscellany):

Now is the time to sing of the floor and the way it is structured;

But my lazy mind shrinks from the enormous task.

Who can grasp and contain the entire world in a poem?

That's what I'm called on to do: the floor depicted the world.

To put it another way: the floor was a mappa mundi. (ll.719-23)

Once again, the skill of the artist is noted, though perhaps more interesting, Baudri goes on to describe how the work needs to be protected from people walking on it:

Monsters and marvels it showed both of land and of sea.

Each thing was named in writing, in tituli close to the pictures:

That was the artist's design, orderly and precise.

Sic ea cura sagax pinxerat artificis

And the entire picture was under a glass-like cover,

Lest any grime or dust sully the artist's work.

"Glassy sea" is the name they gave to this wonderful surface,

All translucent and bright, clearer even than glass.

To protect it from breaking, as people daily walk on it,

There are marble supports bearing it up from below. (ll.724-32)

Unfortunately it is entirely unclear what this description as a 'glassy sea' could be referring to, we don't know if this is supposed to be a sheet of glass or perhaps some sort of lacquer; nor is it clear whether this is meant to describe a mosaic or painting; nor is it clear, again, whether this is meant to depict something that actually exists. (As is typical of poetry in this period, this description of a vitreum mare is probably a double allusion to both Bible and Classical vocabulary; Otter suggests Rev. 4:6 and Ovid, Met. 13.791, but cf. also Virgil, Aen. 7.759.)

Finally, the work of the artist/craftsman (artifex) who made the map reflects the the divine and human artistry that it depicts:

Further, the earth was graced by all kinds of human creations:

The labour of human hands changed and augmented its face.

Some things you saw on the earth were built by divine ordination;

Others, however, were made by an artisan's hand.

Quaedam vero manus fecerat artificum.

The highest artist had fixed and established the courses of water:

Disposuit cursus summus moderator aquarum

Tigris and Euphrates, the rivers Po and Loire. (ll. 745-50)

There are two points in Otter's translation to note here. First, perhaps for the sake of metre, she has made the "artisan's" whose hand is referred to in line 748 singular, where the text is plural (i.e. the things of the earth made by the hand of artisans). Secondly, she justifies the translation of moderator (lit. someone who directs, manages or governs things, Otter suggests "ordainer" in her note on this point) as "artist" in reference to the artifex of the prior line. This strikes me as poetically dubious, since the vocabulary here specifically distinguishes the ordering role of God from the craftsmanship of humans. (There is a string of lines beginning with 749 to 761 where all the major (hexameter) lines and the last few minor (pentameter) lines begin "disposuit...", which means to arrange or regulate, is not a verb of artistic production, but of overarching managerial control. We can compare this with the sagax ... artificis (skillfulness of the artist) that pinxerat (lit. painted) the mappamundi or the studium ... artificis (the care/attention of the artist) that facerat (lit. made) the ceiling painting. Although the point is not entirely unjustified since Baudri does describe God as the opifex operi ("the craftman for the work", i.e. "creation's creator" in Otter), although this is a (again dual!) reference to God and to the platonic Demiurge. Otter suggests Ovid, Met. 1.79: "ille opifex rerum, mundi melioris origo" (that craftsman of things, the source of a better universe) though we may wish to read Calcidius's translation of Plato's Timaeus here too, e.g. in 28a: "Operi porro fortunam dat opifex suus" (Now, that which is produced has its particular craftsman to determine its lot...; trans. Magee).

Note also the authorial insertion through the elevation of the "Loire" to one of the 4 great rivers of the world!

Of course there is a third layer on top of these two layers of artists, along with the manifold other references to artistry in the poem, as this looks forward to the end of the poem where Baurdi presents himself as the artist of the poem, making particular use of the vocabulary of a craftsman:

I have painted (Depinxi) in verse a beautiful chamber for you. (l. 1344)

[...]

Look, my poem's created (coaptavit) for you a custom-made bedroom (l.1351)

Now whether or not there was ever really a mappaemundi in the private chambers of Adela of Blois is entirely unclear. But the poem wonderfully exemplifies how the map is presented as on par with other great works of artistry, like the other tapestries and sculptures described in the work. But once again, the fact that it is 'decorative' doesn't diminish its practical functions: it again serves a didactic function, the poem describes the world as a literary mappamundi in itself, as well as a political function, Baudri has 'painted' a room befitting the station of an eminent political figure.