Yeah I don't see them being able to stream any kinda decent res/quality at any kinda universally playable framerate without lots of lag...
With multiplayer games online you don't tend to feel the command input latency as the client does some prediction, with this method its impossible to do so - your input would have to be uploaded to the server, processed and the frame sent back with the reaction to your input... even an 8ms delay would be enough to make it feel "rubber bandy" for any hardcore gamer and anything over 50ms would be noticeable to pretty much everyone... and I don't seem them being able to deliver <150ms (on average) for quite some time even under ideal conditions. Even those people with low pings to their data center would have 70+ms delay.