Probably right for most big box stores or multibillion dollar businesses. But you would be surprised how thin the margins are for local grocery stores. That 3-5% in processing could be used to compete or undercut big box competitors that price in the credit/debit card fee.

I think with the right approach (small businesses first) it could see high adoption. Plus it would make it slightly more attractive in setting up shop in places that wouldn’t otherwise get any attention (ie, food deserts)