The card processors can't create tailored features because all payments on the internet (that don't rely on PoW and/or have "instant" settlement) require trust, meaning they require minimized credit risk and longer settlement times, meaning they have to take on large fees for all transactions, making small payments infeasible. They HAVE to move over to rails that have at least instant finality, and that's not possible on any fiat rails and won't ever be unless it's as a CBDC or stablecoin. And I also would argue that agents need the ability to send payments without risk of being censored (users would want any task they send an agent to do to be performed without hindrance) and privately (users might not want other agents or users to know who was paying for a task). And the regulatory arbitrage in this case is just being able to avoid the need deal with all the credit bs of the banking system, so that's baked in.