Honestly almost everything works on my steam deck. The only things that don't work are online only games with anti-cheat, and I barely ever touch those. I could possibly make the leap on my main pc to be fully steamos
Especially if SteamOS remains immutable when it lands, then I really won't be able to suggest it except for situations like "my kids have a habit of blowing up their computers" or something.
All I want is for people to make informed choices when picking an OS for a machine. An immutable OS has value in the right circumstances, but if you weren't expecting that it would definitely be frustrating.
My kids play on my Steam Deck so I know all too well how useful it can be lol. I've done many Windows reinstallations in my time.