The efforts from Valve to make the Linux desktop experience better, and especially towards makeing games on Linux actually work has been so helpful in pushing the Linux desktop as a whole to a more accessible, complete state. So many people, myself included, were able to completely switch over and have a more or less good experience, in part due to the effort put in by the developers of Wine and Proton. I know that Valve ultimately doesn't actually care and just sees it as an avenue for making money, and games aren't all that important really, but I think they're pretty fun and this is a big part of why Linux has grown so much over the past 6 years.
About the Steam Deck itself, it's a really neat thing. Being able to bring it with me when I'm traveling or just having another computer that can play games for when my brother comes over is really awesome. I use it at home a lot streaming things from my PC and it works really well. I just like it a lot and it's a cool thing. I can't add anything that hasn't been covered elsewhere already, so I'll just leave it as that. That the Steam Deck is cool and I'm glad it exists and it made me switch to Linux which is fun.