I think it's a reference to awards miles/points... but that's definitely not "for free", you're paying for it with the 2%-3% markup imposed by the merchant processing companies and at the baseline just getting that same amount back on the other side. With that said, with some careful finagling you can get outsized value out of it, especially for flight or hotel upgrades.
It is free because dealing with cash costs the merchant even more than the 3% fees the card costs. If there is a discount for cash it is because they have not counted the costs which are not obvious
It costs a few hondred a month for a cash delivery service. Even if you're only handling a few thousand dollars a day in cash, that's still only around a 1% cost. For most stores, it's probably a fraction of that. Other than that, it's just a few minutes of time to close out the register, which is the one thing employees do reliably quickly, because they get to go home afterward.
For people running a little mom-and-pop business, delivery costs could add up, but they are likely to be in a more-time-than-money situation, and make bank runs on the way to or from the business.
There's also a lot less liability, because counterfeit money is easy to detect, and there aren't any fees or losses from stolen cards or chargebacks.
most of the cash costs are time counting it not moving it to the bank. Those seconds add up. There is also loss to crime since you will get managers stealing from the safe, and clerks form a till - both done in ways you cannot prove. And outright robbery.
Having been the manager at a place that handled a lot of cash, I spent several hours every shift counting all those tills. The clerks might only need a few minutes for their part, but then the till goes to a backroom where the manager counts it again. Then all that cash is combined into piles and counted again.
I've spent plenty of time counting cash and filling out bank deposits, but it was a volunteer position, so we did everything by hand. It's pretty error prone, but we only had to do it once if the cash matched the receipts, which it usually did.
Bill counting machines start at less than $100, and they make it super quick, so accuracy and handling time isn't really a problem any more.
Most retail theft is of inventory, not cash, and chargebacks will easily surpass lost cash anyway.
