I mean we can't really trust both the banks and the whales, banks are just no use since the money you save doesn't really earn a good amount of interest on it as with inflation it just wasn't recommended, whales as well hold a huge volume of cryptocurrency so it just makes the investment risky because when they sell it is going to make a huge effect on the market making it drop a huge percentage.
There is no reason for us to trust banks or whales because their purpose is the same as ours is to earn money to take care of life. No one is good enough to help others without getting benefits for themselves, if in their position, we would do the same as them, all need money.
But I disagree with you saying that banks are useless. Do you use banking in your life? Banks are more than just depositing money and receiving interest, as you said they are an institution and provide a lot of services to users. If you need to borrow money then only banks and centralized institutions can lend you money, bitcoin cannot do it for you.