I don't think any payment process can exist without banks' participation. even if you transact between mobile phones, at some point you need to use the bank to get physical cash for your bitcoin.
The thing we have to know here is: what is this "physical cash" that you're talking about? If you mean paper fiat money, then you are right: you will need a banker...
But BTC is cash. That's what it's all about: no need of bankers, no need of fiat.
Maybe, nowadays, your brick and mortar merchant won't accept BTC, but it's only the beginning. When those poor unbanked people finally start using BTC, ideally it will already be well spread in use as the currency that it is.
If enough merchants accept BTC and employers offer payment in BTC, then you can be your own bank.
