Theres nothing special about them, but i get the feeling they may be for a specific application, and they have a flat dome, maybe good for throw?
http://www.cree.com/news-and-events/cree-news/press-releases/2013/march/xq-intro
Maybe they are intended for large LED clusters? You could make a real wall of light with that shape.
Wide viewing angle for light coming out the side,good for a flooder that’s about it.Doubt the practicality for flashlights but who knows.
Actually, I can see this led in small throwers: small die size, broad spatial distribution -> more of the light hitting the reflector. But it will look a bit weird in a flashlight 
:
“The XQ LED’s new light-emission pattern directs more light towards the edge rather than the center of the package. ”
Throw will probably depend on reflector losses . .
Cubey!
it looks more edible then electronic