Purpose of any modern bank is to make money for its shareholders. It does so by taking money on one side and lending it on the other. Lending is inherently a risky business and that risk must be managed. It's unfortunate that in this process people who deposit money can lose it. Essentially, those people take risk of losing money for <1%.

There is also another aspect to banks which is to provide ability to exchange money. That part of banking doesn't generate a lot of revenue compared to loans so it receives a lot less attention.