Because my HTPC is way underpowered for playing any video game on. I think another angle Valve is shooting for here is streaming windows games from your PC to your linux based steambox. I didn't have much luck using my ultrabook over wifi but after reading it sounds like 5Ghz wifi is a must for that to work because of interference.
Latency playing on the HTPC isn't too bad actually. I was trying hard to notice it and it's BARELY there.
I spent last night integrating Steam into Media Center so I can launch it from there and when I exit Steam MCE pops back up.
