Those larger tents require a chest to store them, you can see one near the alchemy bench in Tomas's tent. And large chests tend to be cumbersome to carry and not ideal when you want to move fast. Could use magic, yes, but not always the best option. And that being said, as
oaiki said they are more desert style shelters. But that particular design is fairly common globally because it is simple and easy to put up when you aren't looking to stay for long. EDIT: I think I even used a similar style in the army while in the wilderness survival training, just made it out of the rain cloak that I had, yes cloak, not coat. Was fine for the few hours of sleep needed before moving to another location.
Truthfully, I would prefer using bedrolls, but unfortunately haven't been able to even kit bash unrolled one that looks proper, or even close to something that is rolled up. Not that there are rolled sleeping rolls that aren't attached to saddles or carts (yes, I know of one, it's old (made almost 20 years ago) and it's going to be a hit or a miss with older meshes. Sometimes they work with a bit texture work, sometimes even that doesn't save them because the mesh itself isn't that good.)
But ultimately, I only can use what is available or I can kit bash. Even trying to find something that isn't a modern backpack or bag that can be used is a more difficult task than one could think. Or even a bag that you could carry relatively easily. The one that Tomas uses is about the only one in "suitable" style. There is one bag that you carry in your hands but it's a viking hunting bag, those were used for small game. Then there was one backpack that was in maybe category. But, if I recall correctly, it had mesh issues and I think I just couldn't make it fit properly at the time.
Unfortunately those kinds of items aren't on high priority for the people who make the assets because they don't sell. So I do what I can with what I have and can acquire...
