This would be an awesome thing. Being able to move between platforms with a similar feel/experience from the windowing system would make life so much easier.
This is great news. I have two controllers (and many hours of fun on Stadia). It really was a great service for me... sat in the Scottish Highlands with a Starlink 'net connection I had the best of both worlds... rural living and a fast enough connection to not worry about latency.
My platform of choice is now a Steam Deck so my first test will be there, hoping it'll work.
This is exactly where we are at home. Some nights after all the kids are in bed and the day is over we will watch a movie or TV. Other nights we have the Steam Deck up and running... my wife isn't really a gamer but she likes to watch engaging games - while reading books - so it works out pretty well.
It just comes down to dividing time effectively. I will admit that is always going to be different for everybody, but we have found it works. :-)
I've been out of the loop with Steam for a while. I used it back in the Half-Life, CS Source, and Team Fortress 2 days. However more recently I've been a Stadia user... it just made a lot of sense with a busy life schedule. Grab a controller and sit down on the sofa to play amazing games. With Stadia coming to an end in Jan 2023 I started to look for an alternative... none, for me, came close to what Steam is offering. So I went for a Steam Deck (with a dock) and a PS5 controller. Valve truly is for the gamers.