Well that's what TriWest does, so its not like they had to search through data to get just that bit.
There's a couple of scenerios in this:
* just a normal theft of computers that happened to occur here
* a terrorist or anti-TriWest minded person that wanted the data
* a competitor of TriWest's that going up against them in a contract bid
What could be done with it? Well you now know the home addresses and relationships of a lot of military personnel. Just that would be useful to someone.