All of the cute, none of the responsibility.
A roommate’s cat is the perfect cat: a cat that you get to live with but don’t have to take care of.
You get to cuddle with the cat whenever the cat is being cuddly.
You’d be a pretty cold-hearted roommate if you didn’t, TBH.
But when the cat throws up on the carpet, you get to quietly back out of the room and pretend you didn’t see.
The closest contact you ever have with cat poop is when the litter box gets mildly smelly.
In which case it is your solemn responsibility to nag your roommate to clean it.