Comment by cornholio

Open just means the implementers of the protocol can select the settlement methods. Cryptocurrency allows in band settlement, but there is nothing wrong in principle with trusting finance institutions that the money really reached your account. So the settlement can be done out of band, using non-blockchain methods by mutually trusted financial institutions, just like credit card payments. It's cheaper, faster, simpler etc.

It's an economic and business problem, not a technical one: the incumbents earn massive fees and have very little incentive to innovate, while the disruptors can't reach the minimum critical mass they require to get rid of the damn credit cards (aka static passwords you need to disclose on the internet).