Depends on the person. I don't think it's THAT good. FOMO took over and I got an entire year right before the price hike on PC. Still haven't used it. I had it on Xbox One X, barely used it.
If you're fine with Microsoft picking out your games, you'll like it. If you want to play lots games as cheap as possible, you'll like it. it certainly has a lot of value, but it depends on your tastes.
At least for me, there are enough games I want to buy that wouldn't be on GamePass that I'd never have time for games that actually show up on GamePass.
If I was a big Xbox fan, and all I owned was an Xbox, I'd get GamePass because why not? I would not buy an Xbox just for it however, if you already enjoy lots of games on other platforms.