What are some real world examples of its use? I've heard of older UBNT CPE's being used but why?
So first off, the best place to ask these questions would be in the ePMP elevate forum... not in the cnMaestro forum, which really has nothing to do with elevate.
Second, Cambium's website gives some pretty good information on what elevate can be used for.
So I'd suggest reading these materials first, and if you still have questions, post to the elevate group.