I went through a bit of a hassle a while back to get a credit card because it would be free of fees. I thought it would be free of fees for the merchants too, which was one of the main reasons why I got it... It now seems like the merchants are being screwed and everyone else are getting points and free trips on their credit cards.
I'll need to take another look at this, but there seems to be little reason to use a credit card instead of a debit card, unless you really know how to take advantage of it.
Credit cards do cost the retailer money to use (the amount varied by card up to a few percent of the transaction, with AmEx being most expensive). It can be expensive, but if you have a business where consumers want to delay payment (and there are valid reasons to do so) it grants the retailer immediate payment and no risk (as opposed to the retailer granting credit themselves where they bear the risk and have to wait for payment).
And often it was just simpler. At the moving company we requested credit card because we could put a hold on the funds before the move, but only take payment afterwards once all charges have been finalized. In addition we had people paying over the phone using their credit cards.
Yeah, using a credit card is often to your advantage and the retailer's disadvantage, but retailers do have potential benefits to the cards as well.And most places already factor credit card fees into their pricing, so unless you get a cash discount you are probably paying for someone else to benefit from their credit card when you pay in cash.