Well, there isn't much added technical complexity here. This is more or less a glorified "download a .repo file for your distribution and put it in your /etc/yum.repos.d" directory with a Nautilus plugin. And yes, I'm pretty sure a lot of people will not bother with Extras, if only because:
a. They don't care to jump through all the hoops involved.
the hoops are getting lower and easier to overcome.
b. They don't want to bind themselves with any sort of a contract with Red Hat.
the cla is very much like the asf's licensing agreement - nothing really special in it at all.
c. Their software is licensed so that it cannot be put in Extras.
yep. that's the use case I figured from the .fap file you were describing before.
-sv