if i build a bank of bitcoin that operating like a traditional fiat money bank when people can save the money and get interest for their saving and also people can get a loan from my bank but the fiat money is change for bitcoin, the question is would you guys trust me to save your bitcoin on my bitcoin bank that i want to build ?
The purpose of Bitcoins is to get away from banks, and not have them store your money. Also banks are allowed to lend out 7 times the amount of money that they have from the public. You cannot do that with Bitcoin. And where are you going to store the Bitcoins? In a Bitcoin wallet? People can already do that for themselves, unanimously, private from most people. While you'll be a major target.
We cant just choose one of them. Both sparkling options have their own benefits. If we talk about bitcoin, you know how safe they are and how beautifully they help people to earn money. And likewise, for banks, they are safe too and investing your money in businesses and giving back some profit ratios for your benefit. So whatever suits you best, go for it.