Does anyone have any data to show if this is done on servicemembers or for their spouses? I don't see a big deal either way - I'm just curious. If some E5 wants a set of bolt-ons, I don't see it as a problem.
My guess (purely guesswork) is it probably done for those "in the know" - nurses, lab techs, docs' wives, etc., who discover that one of the plastics guys on staff likes to keep his skills up and is looking for practice. Considering the extremely low number being done, it's definitely not something that most active duty folk have a clue is available.
Hubby's an Army dentist and does a certain amount of cosmetic dentistry (only on active duty troops) on folk who seem interested and motivated to take care of it. Also, only when he's not swamped processing reservists with grunge mouths just called back to duty.