While this is true, I've seen plenty of bank-backed ads basically stating "please try paying by card even if it's a small amount, it doesn't cost you extra anym

While this is true, I've seen plenty of bank-backed ads basically stating "please try paying by card even if it's a small amount, it doesn't cost you extra anymore", sending practically free money towards Mastercard and Visa. Participating banks or even governments could easily set up an equivalent advertising campaign for their new system. The ability to have mobile payment without the prying eyes of the American government alone could be a good ad. I'm sure Trump will start another trade war if an ad actually voices that benefit, though. In theory, merchants can choose not to support certain payment processors. I can imagine a minimum-price supermarket chain like Lidl eventually dropping Visa and Mastercard to cut costs, for instance.