These controllers were all working on SteamOS before as far as I know, so I’m interested to see what this changes. My understanding is that previously their controllers just show up as generic xbox controllers, and now they will be properly recognized. We’ll see if this has any other benefits like custom bindings for back buttons and things like that.
It sounds like they have to wait for support to move from the Steam Client Beta to mainline. That happens on Valve Time, so they genuinely do not know.
Then they shouldn’t say anything.