ACH for B2B is a significant chunk of that money, so is payroll. It's also admittedly misleading because the card networks use ACH significantly to settle money from Bank A to Bank B (i.e. on "the backend").

This is poignantly addressed by @PC's comment addressing whether or not this would be available with Stripe Checkout.

ACH, for now, is generally terrible in retail situations. NO one wants to wait an additional 2-3 days (to all for funds to clear) to see their shipment be sent from Amazon. There are some niche use cases where it may work for pay-ins, for example online custom wood shops—where there's a built in delay to build the product—or other services where physical products don't need to change hands.