Yeah I've had it running and streaming! Have run a few games this was - ARMA3, GTAV, South Park: Stick of Truth. All worked well. Have also tried running the windows steam client in WINE and had a few more issues, but as ever YMMV.

The performance isn't quite as good (very close to windows perf levels), but quite a few anti-cheat systems will not work in Proton (even less so in WINE).

> quite a few anti-cheat systems will not work in Proton

A lot of interesting "hacks" (sorry for calling gaming on Linux a hack) are made impractical by this.

Another is that you can buy a miner's GPU (no video output, but much cheaper) and modify the drivers to route video through integrated graphics VO. Or, modify drivers to support SLI on any nvidia card. These driver modifications require running Windows in a special mode, which triggers anti-cheats. Maybe there's a way around that. Haven't heard of it being attempted on Linux. By the way, these driver modifications are just removing artificial restrictions.

I'm perfectly ok with some games not running as well as Windows, or not even running at all, in particular if I could also play them on console. I was more worried that Proton would not work reliably with streaming at all because it has to go through all these hoops to get an image on the screen in the first place. But it seems this is possible, which is great.

Games with anti-cheat not working doesn't bother me either as I don't play any games online anyway. So the intersection between 'games I play' and 'games that need anti-cheat' is very small ;-)