As someone who owns both and a PC as well, yes. Playing my steam library in bed is incredible. Also, if you have a larger library, it can be cheaper to just buy a Deck than re-buying everything on a different platform.
I haven’t found anything personally that I want to play that I can’t play as I play a lot of indie games and singleplayer games. Proton is pretty incredible. YMMV though. If you play games that heavily rely on mouse and keyboard and twitch reflexes, or any game that has strict anti-cheat/DRM, you might have a suboptimal experience or not be able to play it at all.
You'll be able to play any game that can be run on Proton (Valve's Linux compatibility layer). Technically, you can install windows on the deck and then run anything on that, but that's not supported out of the box.
I have a PC and a Switch and despite liking it a lot when I had it from a friend, I decided against getting my own. Mostly based on the fact that I already covered all my bases:
I can play at the desk.
I can play at the TV (Moonlight in-house streaming)
I can play PC games.
I can play Switch on the go, and I got more than enough games in my backlog that I don't need more games for that.
But if you game a lot and are on the road a lot, I would say it's a damn good investment.
For me I’m not a huge fan of the form factor and prefer to play on a TV or at my desk. If I don’t have a good PC already, though, I’d definitely consider getting it.
That's something I had been considering but at the time the support for docks was really bad, so using it Switch-style and docking it to a TV was a no-go. I heard it's really good now though, so that's an interesting thought.
Maybe. I have those two and a PC and I think the Deck is essential. But I do really like being able to seamlessly pick up my games on my main machine sometimes too. If I didn’t own a PC or a PC game library it might be less enticing but even then I still think it’s worth it. You may struggle deciding where to buy games though and you will probably end up building a gaming pc if you enjoy the Deck.