Little known fact: Major debit card interchange is regulated by law at 0.05% + $0.22.[1] That's right, a twentieth of one percent. The gross margin for a processor like Stripe that charges 2.9% + $0.30 on these transactions is just astronomical. A U.S. payment gateway that specializes in low cost debit card processing arbitrage would instantly start saving startups money. It also give them the option of steering their customers to low cost debit, for example by requiring it for discounted annual subscription rates.
This would work where other efforts have failed. Crypto never took off for consumer payments for a variety of reasons, among them no wallet penetration and no consumer protections. ACH is inconvenient to set up and also has poor consumer protections. Debit cards on the other hard are widely available, safe and easy to use.
[1] https://www.burlingtonbankcard.com/home/interchange-plus-cre...