Most countries have some kind of bank wire system that is in charge of the money itself. Cards are pre-authorization system. The movement of money is authorized

Most countries have some kind of bank wire system that is in charge of the money itself. Cards are pre-authorization system. The movement of money is authorized when you swipe the card, but not actually moved until up to a few days later, through the existing bank wire systems. If there's a currency conversion involved it can be even trickier.