@Aj33, an in-law is a little more like an Entire Place, and a Guest Suite inside your residence is a little more like a Private Room.
But really you can make a strong argument to list both In-Laws or Guest Suites as either an Entire Place or a Private Room.
The difference is mostly about whether there is a separate entrance from the outside.
Again, there really isn't anyone at AirBnB checking the listings for accuracy. The main issue is helping the guest to understand what they are booking.
I also understand in certain cities, the different room types are treated differently legislatively.
In that case, there might be an actual outside authority who might want to decide what kind of space it is, but one generally hopes it doesn't come down to that.