Even in the age of computers each transaction has a cost and a risk associated. And there is no upside to large companies. They don’t want to receive per-minute payments any more than they want to send them. So if 95% of a business’ volume works one why, why invest in making 5% different just to deal with smaller vendors, who are already more difficult to deal with (for 100% good reasons).

AWS bills in seconds in some cases but still invoices monthly.

Right? Even cloud computing companies which technically charge you per-minute pricing end up rolling it into a single monthly bill at the end of the month instead of a CC transaction literally every minute.

In the repo market (overnight inter-bank lending) Fedwire daylight overdraft interest accrues every 15 minutes.