I wonder why Valve is bothering with this. People who use Linux exclusively are probably too small of a market right now for this to be a profitable endeavor. Maybe they're gearing up to revitalize SteamOS and Steam Machines?
Other than legacy enterprise stuff, gaming is the one area where consumers continue to be tied to Windows. It seems like a no brainer for Microsoft to lock down that market. The average Joe/Jane that needs to do write some emails, pay bills etc. is fine nowadays with an iPad, Chromebook, etc.