For me the killer feature of Steam for Android would be if they offered Android versions of games I already own the same way I can play all games with Mac build

For me the killer feature of Steam for Android would be if they offered Android versions of games I already own the same way I can play all games with Mac builds on Mac. Although the list of games that exist both on Android and Windows is small I can think of enough games on Steam (GTA3, Max Payne, World of Goo, Osmos, Anomaly, Popcap games, etc.) to make it an attractive feature.