Walmart was very supportive of fedNow for the express purpose of removing MasterCard from cashless purchases. And for a long time the only way to pay by phone was to allow them to debit via ACH. out of all of them they get it the most.

https://news.ycombinator.com/item?id=36012866

And really, even banking isn't a safe harbor. I am pretty sure they were at the forefront of the rise in neobanks and products like green dot cards.