I built myself a new gaming desktop and set up my old one next to our TV, telling myself I'd get it all situated with controllers and my large library of split screen games. We have a Shield TV for most streaming, so the desktop is pretty much only used for two things:
My wife watching Chinese shows on random websites and watching movies remotely with friends over SyncLounge[0].
So while the Steam Machine is intriguing, I really don't have a good reason to buy one. That being said, I like the idea of supporting this kind of hardware development.
If I purchase one it is effectively a console-killer for the big screen. The fact that the PS5 is now in the twilight phase is making me consider it. The era of exclusives is almost over as basically everything I want to play on PS5 is also available on PC.
At the same time I don't need a living room machine to be a full-fledged desktop. Nor is that desirable with kids.
I don't have much reasons to buy one either, besides "It'll be fun to thinker with" and "I want to support any company trying to make Linux go mainstream, because ultimately that'll make my desktop experience better". But those two feel more than enough, and I'm happy to open my wallet for them.
So while the Steam Machine is intriguing, I really don't have a good reason to buy one. That being said, I like the idea of supporting this kind of hardware development.
[0]https://github.com/synclounge/synclounge