Rewards are taken from merchant fees. The retailer isn't party to that rebate. Likewise, coupons are almost always funded by the manufacturer who returns those monies to the store.

"Rewards are taken from merchant fees."

That would be true for credit card fees, but not for stuff like loyalty card discounts.

"Likewise, coupons are almost always funded by the manufacturer who returns those monies to the store."

It doesn't matter. The store is the one charging the customer. As stated, the law says the store cannot charge SNAP recipients more. Thus it would be a violation if we are taking it strictly.