I actually found one good use for the vault. It might be old news but I'll say it anyway. If you want to add a new sim to your household through CAS, you can stash your fortune in the vault so you won't lose it, since your household funds get reset once you add a sim (I don't know if this is a bug or if they did it on purpose), I learned that the hard way. Just stash absolutely all of your cash in there and then just sell the vault when you get back, and you'll still have your fortune as well as a 22.000 bonus. ;)
