Full stop. Credit cards provide a service and that service isn't free. It gets factored into prices.
https://www.merchantmaverick.com/the-complete-guide-to-credi...
I'll add that Visa charges 1.43% - 2.4% of the transaction. I'd be curious to know what the cost of a cash transaction is as a percentage of the transaction. I doubt it climbs that high.
Also, better hope your cashiers never make a mistake or accept a forged bill.
I can't resist an aside. A buddy of mine was in a well known cash business. You can imagine. Anyways, hanging out with him, we'd be driving around and he'd need gas. He'd pull out 2 or 3 $20s, hand them to the attendant pump gas and go. Some gas stations gave a cash discount.
It seemed to me that credit cards were supposed to be fast and convenient, but if you're choreographed for cash, it ain't so.
This is very apparent in (many parts of) Europe. Cash is so much faster there than in America, for a few reasons. The primary cause, I think, is the fact that the prices are generally round numbers, with tax included. This means that you can, in most cases, pay with a small number of coins or bills. In the USA you'd be wrestling with pennies.
Re your last point: it's probably a similar risk for us as charge-backs.
Customers offer to pay cash thinking it saves us money, they're wrong.
But it's so much cheaper than handling credit cards that many small stores in Germany won't accept any cards at all.
The cost is much lower on a debit card transaction.
Mostly because their fees are even 10 times lower than MasterCard's debit card fees.
The fees for the German Girocard system (which is what colloquially is still called EC) are lower than MasterCard's fees but not by that much anymore nowadays. MasterCard debit should not be 50% more expensive than Girocard considering all fees (which of course still is more) if you shop around a bit. Even Aldi takes them now and they try to save money wherever they can.
Well, Aldi only takes some type of MasterCard debit - only the Chip + PIN edition Maestro cards, not any of the actual MasterCard network, nor mixed credit/debit cards.
Things have changed considerably in the last two years and whatever one knows about cards, acceptance, and fees from before 2015 can safely be forgotten.