Certainly anyone else can give their opinion, but I would like to link back to my answer to How well does CGP Grey encapsulate the experience of a historian? which focused on my impression of the Tiffany video. The short version is that I didn't think it does line up with my experience of doing history in its narrow focus on finding and documenting instances of a word/name - my experience is of either studying many primary sources and drawing conclusions based on that large body of knowledge, or reading widely in secondary sources on related topics and building an understanding of an aspect of the historical world.

So for instance, the obsession with trying to track down a poem presented as very old in a mid-19th century text is not something that's generally going to happen in a historian's work. Not never - I can picture someone going down a rabbit hole - but not to prove that "Tiffany" was considered a woman's name in the Middle Ages a single time. And his rabbit hole seems to continually branch into totally unrelated subjects, while at the same time he failed to note e.g. the misspellings of the family's surname or look for variations in the spelling in the first place! (Historians who study early modern England know that spelling was optional, especially with names. And that early modern historians are not super reliable sources in the first place, so they wouldn't fixate so much on the idea that Hearne Knows Something that they can know too if they look hard enough.)

If I go down a rabbit hole, it's going to be more like ... say I'm reading about how actresses in the 18th/early 19th century managed their wardrobes for the stage, which they had to provide, and the relationships they had with dressmakers and the fashion industry. I might decide to look up some more info about Sarah Siddons, a famous actress from the end of the eighteenth century, and then when I read about how she appeared onstage pregnant, I get a book on views of pregnancy in Georgian England to better understand that aspect of her life. Or I might get frustrated with the lack of info on specific French dressmakers of the time and get into the primary sources, reading/skimming issues of early nineteenth century French fashion magazines to see if there are any mentions of who is making these clothes - I'm just going to sit down and look through Le Journal des Dames et des Modes from 1800 to 1820, going through every issue. In both cases, the focus is on broadening my understanding of a certain facet, which generally also leads to a broadening of my understanding of the period in general; reading the primary sources en masse may give me new avenues to look through as I start to notice how many garments are associated with specific performances.

I don't begrudge him his fun going into all of this, but it's not much like what historians do, in my experience.