There are a ton of these out in my neck in the woods. Two main styles:
Barn and house attached via breeze way.
This is what we have. You transition from the house through a mud room/hallway and a door leads directly into the barn tackroom. I didn’t think I’d like it as much as I do. It’s FABULOUS for rainy days, night checks, colic watch, etc. You can just walk out in your PJs and check what needs checking, without dealing with the elements. Also, no need to have a bathroom or sink in the barn, as the house bathroom is literally just yards away. The plus side of this plan is the house and barn can both be independently as large/small as you need, but the “footprint” is big, and you need to have a property that can accommodate that size. Also, having the house attached to the barn limits the 360 space around the barn if you’re trying to maximize easy-access paddocks and runs.
Barn on ground floor, house/apartment over it. I’ve seen several of these. You need to have a large enough barn to support a large-enough house (ie, probably not suitable for a 2-stall job - a 4 stall w/ tack and feed rooms is just enough square footage for a small 1-BR apartment). the “footprint” of the overall structure is smaller than the above setup, and the heat from the barn helps insulate the house portion. It does preclude the option of having a hay loft, so you’d need to figure out alternative hay storage. You also always have to climb stairs to/from your house.
I can’t speak to the insurance considerations, but even in a relatively mild climate, I love the convenience of having the horses right next door, and it’s SO nice when it’s dark and snowy and you have to go feed. You don’t have to slip around or get wet if you never leave the building…