It would be nice to see this potentially lead to an app store for Steam Big Picture[1]. At the moment, I think that's one huge thing it is lacking.
Sure, I can load up YouTube or Netflix in the browser. But the interface is clunky and buggy, the video playback is choppy and it often simply crashes Big Picture.
Adding apps, I think, will make it a must-have living room device for gaming, browsing the web and consuming media. And the possibilities from there are pretty much endless.