I could see Debit Cards being replaced by direct transfers.
The issue is what happens if who you pay too does not provide the srvice or just runs off with the money.
Under UK Law the customer can deal with the Credit Card issuer and get their money back with a direct payment it is npot always possible.
For debit cards I think the issue will refund if fraudelent but might take a battle. With direct payments the customer has a much harder job.
its cheaper but customers lose protection for doing it, and as its illegal (yes, against the law) to offer them a discount for using debit cards, cash, or direct payments they have no reason to.
But the problem is that if you use it to pay for a service and do not get the service you can only claim off who you paid and that requires taking them to court while Credit Cards just require phoning up the card provider. Debit cards are between the two.
I have not actually used it. I have paid some people (mechanic, gardener) with a bank transfer which works well thanks to faster payments being near instant.