A bank ingame should be what a bank is in RL - a place to deposit/borrow cash.
Clearly there should be a way to store items for a trader. But at higher costs. And with SOME higher security. To steal things from Boston you would need a highly trained criminal, but on the other hand you should have a fat bounty on your head set automatically by the city and be arrested as soon as you step foot in the zone. And thrown in prison for a considerable amount of time. Maybe make a jury out of randomly selected players and have a sentence picked (from min to max). Imagine the fun of public trials, once in a while ending a fun public hanging.

And alt storage sux as game mechanic.