This seems like a common feature when looking at the design of old palaces. Instead of having a hallway with doors leading to each separate room, the rooms themselves are the hallway and each room just opens into the next one.
It's like that at Hampton Court Palace and Versailles. But, I'm certain there are more. We know they understood the concept of a hallway, because others parts of those palaces do use them.
I would have figured rulers commissioning such palaces would have had a care for their own privacy and comfort. Instead, they designed their palaces in such a way that their servants and guests would have to pass through private and possibly occupied rooms just to move about and fulfill their duties.
Is there any particular reason for this design feature?
The concept of palace is different than most people would think. This is the cause of many of today's mansions, which attempt to emulate palaces becoming full of silly and redundant rooms (ie, Aaron spelling house has a Christmas present wrapping room...) Or are like 15 bedrooms and 30 bath when they will never have like more than 5 people ever stay in the house.
Why is that?
Our concept of what a house is mixed with the very different concept of a palace.
It would be like having a private home be made to resemble an airport. And you might ask why an airport is all hallway and no other room types.
So let's start with what palaces are:
They are government buildings first and foremost. Not houses.
Second, in the era they were built (ie post fortification) construction and architecture were the primary ways to display power and wealth. The very existence of these rooms weren't a function beyond being big and beautiful.
These rooms are known as state rooms.
They are large rooms that are very nice and overwhelming to visitors. They can be used for things like balls or dinners, but they are first and foremost simply fantastic. Think the Jordan stairs at the winter palace or the great Hall of mirror at Versailles.
And these room types take up the overwhelming majority of the footprint of these palaces. These aren't rooms where people "live".
So, about living...within these palaces there are "apartments" where royalty would live. Just like an apartment within some larger complex. These apartments are grand, but are on a more normal scale of homes for people. And within them, you would find more normal amenities, modern design and conveniences etc.
In fact, palaces were so busy and formal, that most monarchs had secondary palaces to live in. Think the grand trianon by Versailles, and the ppetit trianon near the grand trianon not!!.
Andt to the winter palace and the Summer palace of Peter the great.
Even Buckingham palace is the side residence to the "actual" Royal palace, tye palace of St. James. Which was the side palace to the now gone Whitehall.
Anyways, on to hallways.
The style of room layout you are referring to is called enfilade.
Enfilades are primarily a baroque thing. They allow the awesomeness of the rooms to be beheld. Without going through the dissapointing ardour of a hallway, wich is a service type of room (all rooms in the world are either servant rooms or served rooms), not a room in it of itself.
And so, with this in mind, you want your visitors to go from one splendid room to the next, each more glorious than the next, and so each room needs to be traversed individually. Nothing skipped.
And so, each room is progressively more grand and awesome, each representing to the visitor how much they are valued (the more important, the further in you're allowed), often culminating in the throne room at the end.
So this is why no hallways: it's beneath the palace. And to serve the purpose of overwhelming visitors, you want them to go from room to room, not skipping rooms with a hallway.
Besides, palaces are very skinny (usually some squarish/rectangle/U shape with a large Central courtyard), so there are only one max two rooms per space in a palace. So a hallway would be without windows, which would be dank in an era before electricity. Better simply have a grand room and call it a Hall, and not a hallway.