Yeah, this controller is definitely for "PC type" gamers.
Most fighting gamers prefer to use wired USB fighting sticks anyways, and given that those sticks tend to work out of the box on most operating systems, I would expect them to work on the Steam Machines too.
IIRC, Steam only really has three modern fighting games (SFIV:AE2012, SF vs Tekken and KoF13) -- I don't know that Capcom or SNK would plan to port those Windows games over to Linux anyways -- you'd likely have to play them streamed, and I'm not sure that any serious fighting gamer would want to do that.
Most fighting gamers prefer to use wired USB fighting sticks anyways, and given that those sticks tend to work out of the box on most operating systems, I would expect them to work on the Steam Machines too.
IIRC, Steam only really has three modern fighting games (SFIV:AE2012, SF vs Tekken and KoF13) -- I don't know that Capcom or SNK would plan to port those Windows games over to Linux anyways -- you'd likely have to play them streamed, and I'm not sure that any serious fighting gamer would want to do that.