Great point you make here. The main point of cryptocurrency is for us to be our own banks and keep our money away from banks as you stated. The banks take our money...invest it for us and still charge us fees which absolutely makes no sense.

As far as exchanges, there are definitely necessary for now. Exchanges offer simplicity in trading coins. Yes, they are susceptible to hacks, but users can take precaution by using wallets and not sharing data or clicking wrong links.