> You go to your bank website and obtain a random number, either allowing a single transaction or a recurring transaction. You give the merchant the number. After merchant charges it, no other merchant can charge the same number.

That's basically how Blik works in Poland. With the exception being that the number is random 6 digits randomly generated when you open the app, that is active for ~2 minutes. So you don't deal with the issue of very long and error prone numbers to copy.

Much better way to pay online.

https://en.wikipedia.org/wiki/Blik