The game currently has an anime adaption that just started airing airing(though the blu-ray preorders were pretty poor the last time I cheked so I'm surprised it did as well as it did) and the Vita is pretty much for Otaku at this point so that could have something to do with it.
Meh, it won't happen I think, but I wouldn't mind if they release that kind of stuff in the west. Maybe digitally since retail is even more impossible, I guess.
I'll buy stuff like that for my Vita no problem. Anything to add Vita's not-so-healthy roster of available games.