With their recent dashboard update and avalanche of new streaming video content, it's clear Microsoft is working aggressively to expand Xbox Live with content beyond video games. Just because they want more apps online doesn't mean they don't have standards, though. From here on in, every Xbox Live app must have (technically) functioning motion and voice controls in order to get approval from Microsoft.
Saying that they now require Kinect controls doesn't really stress how serious Microsoft is about this. Let's put it this way: There are only two required elements for a Xbox Live app: Kinect support and parental controls.
It makes sense, really. The appeal of using a Xbox over an internet-enabled TV, Roku or any other streaming device is the ability to do everything without ever getting off the couch. Microsoft is courting lazy people and they know it. Also, the more companies that use Kinect, the more reasons we have to buy them.