I think the MarketPlace is a great idea. Both as a platform for people to sell things, and as a place to purchase things. As a programmer, I suck at making my own assets and if I’m just prototyping I think it would be great to just buy a rigged and animated character or whatever off the MarketPlace.
The more people using the Engine will make it better as a whole. There is some myth that Unity is the defacto engine to use as an Indie developer and I am hoping that sentiment will change. But, Unreal needs features such as the MarketPlace for that to happen.