Well what if MS tries pushing Games for Windows again?
EDIT: Ah it was mentioned, anyway, this could be their attempt to bring back the concept and create an Xbox Live service based PC regulation environment.
Since Miracast is a feature of Windows blue, there is a chance that MS might allow any service to stream games from the PC or supporting mobile device to the X1. Depending on the minds working at MS, it probably would be better to expand the uptake of Windows blue and X1 by opening up the technology for any service to use then just their own. By opening it up to everyone, it would increase the chance that other services like GOG, Steam, Origin and other players to make their games stream this way. It would increase interest for people to get Windows Blue and X1 just for this ability. Next thing you know, if the service opens up for Emulation then MS would have a killer app.
People who believe MS woudl not allow this have to remember that MS is looking to expand their products. Sometimes it make sense to keep things only on your service but then there are times when you need to be as open as possible to make your 2 prime products separate themselves from the competition. Windows 8 needs more consumer traction and X1 needs something to separate it from the PS4.