This is awesome and definitely zaps one of those features Steam wanted to bring to the living room. Plus it also explains why Microsoft recently confirmed adding mouse and keyboard support to the Xbox One. So maybe you will be able to work on Excel from your big TV! (Or what actually might be useful, it stream say a power point presentation from any PC/Xbox One to any other PC/Xbox One - without worry about flash drive and spread viruses, compatibility, etc.
It is a good question will it only work with DirectX games or also Steam?
More features on your devices are always good.