1: https://www.delish.com/food/news/a37579/chipotle-caught-roun...
The discount has to reflect the fact that the cost of dealing with the cash isn't too far off the actual cost of paying card fees now. To the point where cash is so rare in Australia that cash handling companies are in trouble [1].
Our Reserve Bank recently suggested that businesses might soon want to charge customers who want cash /more/ - it seems possible that at some point in the near future anyone offering discounts for cash will just be instantly flagged for tax investigation!
1. https://www.abc.net.au/news/2024-06-05/fresh-accc-scrutiny-o...
I think at one point I've even seen 4% cash discount and 4% card surcharge in the same place. And I doubt that even the most expensive payment service provider out there charges the merchant anything close to 4% for card processing.