With Gamepass Ultimate you can do that without even buying it ONCE! Out of all the subscription services I pay for these days, I feel like Gamepass is one of the better values. YMMV of course, but I love it.
Sadly, nothing good remains that way forever. The structure and terms of Gamepass will eventually change to something less optimal.
Right now, the focus is to draw in people and create a "loyal" userbase.
Once they're content with the state of the userbase, they'll start restricting access and features to make people pay extra for different "premiums" and it'll slowly go to shit.
I guess. But it's been pretty good for years at this point and it's pretty easy to get REALLY good deals on it if you keep an eye out. I got three years of Ultimate for like $120.
Either way, just because it may get worse later is no reason not to take advantage now.