Obviously a convenience thing. It is really annoying when you need to clear out space in your vault and your having to bring a few weapons out at a time just to dismantle and having to repeat the process over and over because you only have a few slots open on your character anyway. Why not just add being able to dismantle from vault? It would make not having space in the vault a little more tolerable. Also being able to select more than one thing to dismantle at a time would be awesome!