This is actually a genius move. Everyone is so concerned about the 12% and its rivalry between Steam, and not see this from an Unreal Engine perspective. Instead of Getting 5% from the Game sold as EPIC are currently used to now, they are now getting 12% with an additional Gaming App Store. That is an 240% increase in revenue with very little additional offering.

Unfortunately I think Unity May see this as a threat, Now what if Unity decide to make an App Store for 7% revenue, which should effectively be a non profit model after you take away the 3% Credit Card charges and CDN cost.

Anyway both would be good as we continue to push forward the Middleware Gaming Engine.