Yes there are lots of problems with banking. Cryptocurrency does have a reason to exist, though of course we went and fucked it all up. It can help ordinary people outmaneuver oppressive regimes. It can perform that same core functions that banks can (i.e. keeping track of and moving around money) in a public and distributed way. The banking industry (often metonymically known as "Wall Street") is literally the canonical example of greed. There are problems with banking. In a better world, crypto can distribute the power of money. But, since it's a technology born within the system, it is instead used as a way of amassing value, and in the end only making the rich richer.