I also think that a btc bank would turn btc into a non-reliable currency.
Except being an unreliable currency there would be no difference between bitcoin and other ordinary currencies, now almost every bitcoin users think that they have a financial freedom because they are their own bank and they don't need any third person to get involved in their monetary decisions and if a bank is introduced that freedom would be snatched.
it would chance nothing for you if you would not use it. just because there is a bitcoin bank does not mean you have to use it. you will be able to still be your own bank. and if a bank fucks up, then they will have to close. since they can not print money. maybe the best thing to teach people is to let some banks fail and let them lose all there money. until they do it on there own.