The difference here is that banks are singular entities and the witnesses are people we vote for.

Another issue is that Justin with the SiNMS has the power to become a singular entity with the power to freeze accounts or alter the blockchain. His plan is to destroy it and reopen it on his Tron blockchain.

If witnesses aren't doing what we want, we can always have campaigns to replace them.

But we cannot easily replace Justin. He bought his way into power.