Cryptocurrencies are completely free of the control of third parties, unlike Banks. This decentralized nature minimizes human interactions, which makes them free from biases. They are more secure and reliable since it is hard to tamper with them because they use anonymous ID numbers in transactions.
Keep in the bank. For bitcoin, it is short term or intermediate term business. It is volatile and probably not sustainable for long. It is also decentralised so if across the world , large amounts of it is removed, its value is affected keeping your money on the bank might be safer because it won't be volatile.