Banking industry is centralized and it defeats the purpose of using bitcoin, let's just admit that we cannot achieve big growth like making majority of people adopt with bitcoin as they certainly would choose the fiat system or any government regulated currency, and that's for security reasons
We should separate the wheat from the chaff
Fiat banks are centralized in a sense of being regulated by the laws passed by governments. A bank which breaks these laws loses their banking license and ceases banking operations. But banks are basically free in respect to how much money they can create (in certain limits, of course). In this way, they are decentralized even higher than Bitcoin miners which can create only as many bitcoins as firmly set by the current mining reward. On the other hand, the whole Bitcoin network is no less regulated than a banking system, I mean by the Bitcoin protocol. Some folks here claim that Bitcoin is even more regulated than any fiat system out there (if you are going to challenge that point, don't attack me since it is not my point)
Yeah mister Cat-Pilot! But can we really separate banking system from its legal regulation? Both seems completely symbiotic don't they?
Bitcoin network is much less regulated than the banking system we know because banking system in our world needs governmental approbation to even exist.
But as you seem to have thought a lot about the question I have a question for you: what would be the point of a bitcoin bank?
I mean, a fiat bank has a very simple purpose, making money, and a simple utility for most of its users: providing a stock and exchange system. Banks were created for that, you use a bank not for the interest rates but because you NEED an account in order to send and receive money, because no company will give you your wage in cash, no government will make it easy for you to pay your taxes with cash, and even if all that was possible you would still want to stock your money in a "safe deposit". Of course interest rates are a plus, but you would use banks even if they had 0% interest rates!
But bitcoin already allow all of that. So what would be the main goal of banks?