How does FeaturePoints.com distribute its iOS app to the public without the App Store
They probably use the iOS Enterprise Developer program you mentioned. This happened before, for example with GBA4iOS. When this comes to Apple's attention they usually do something about it though.

http://readwrite.com/2013/07/17/apple-slams-the-door-on-super-mario#awesm=~oyiYU7RMNByRFi