Unless I'm reading this incorrectly this is a peering arrangement, which is qualitatively different than just hosting a box in a DC run by Comcast (which doesn't exist, as far as I know, so I can't do it as a normal citizen). I could colo a box "near" Comcast, but I'll be more hops away (worse performance) and I'll have to purchase transit from some ISP that does peer with Comcast (more expensive).