The Blockchain provides an audit trail that is considerably more transparent and easy to access than the audit trail a bank uses.
I agree, bitcoin is not out to replace banking but it can offer banking facilities to those who cannot get them and banks will adopt bitcoin for the benefit it provides them, in all likelihood bitcoin will underpin financial transactions without the end user knowing particularly with regard to international transfers.
It is not about paying for things with botcoin, for the poor most banks won't touch then because they are not financilly viable, ie their income is to low for the bank to safely lend them money (loans, overdrafts, credit cards) as a result they don't even get to access the basic hold, send, receive money services.
Think of international remittance, a worker wants to send money home, he wants to send $50, Western union charge 10% of that, a bank would probably charge 20% to send it to Philippines. This second option requires the person in the Philippines to have a bank account, which is not always the case. The first option cones at significant expense for the sender.