But why we need banks to store our crypto currencies?

Actually this is against the crypto currencies,because the main reason of crypto currency invention is making transaction without any third party help.But now they are banks involving here so they want to control our money that is what they are doing for centuries now they are coming to the crypto currencies too.

We can store our crypto currencies safely without anyone's help and we just have to store our private keys safely.So people don't want any banks to store our crypto currencies.