Originally Posted by
greenbed
It has nothing to do with tap/swipe/insert - its related to the interchange fees charged to businesses for processing the card. Amex offers payment networks such as square and toast lower interchange fees vs traditional payment processors at restaurants.
For some reason I was thinking the issue was only with tapped transactions and not with other methods.
In any case, AFAIK there haven't been any issues with grocery transactions and the majority of those are likely at larger chains (which probably pay less too). I'm not sure fees are the complete story.