bitcoin banking is probably ponzi. simply because you are hardly earning a decent interest with the blocks halving, really man.
even with the mining, you won't gain a lot of interest in bank; again, halving.
nope. they can create a business of saving customers money, or lend to someone to make a profit
OR they can simply pack their bags and leave when they have enough money of the noobs who don't think twice before sending money to these so called banks.