Yeppers. They upped my Xbox game pass ultimate by I think 2 dollars so with tax is like 22 bucks a month. And I only use it really to get games and play online. And EA play to play NFS / F1 games but anything else that's included with ultimate subscription I don't use ever.
Yeppers. If you don't have Internet, it can't sign you in with your Xbox live profile and kicks you out of your game trying to make you sign in. In this case majority of the time it's not the users internet, it is Xbox live servers being down. I swear this happens at least once a week now. Happened to me like 4 times before. Hey, I got free time, let's go cruise in Forza, nope, Xbox servers are down.
All online multiplayer games need Internet or Xbox to be actually working since the game has to sign in with your Xbox account to actually get and save your progress and other stuff.