The merchant complaint is legitimate: Many credit cards have variable rates depending on the type of credit card. Many premium cards have higher transaction rat

The merchant complaint is legitimate: Many credit cards have variable rates depending on the type of credit card. Many premium cards have higher transaction rates and a merchant is forced to accept all cards of that brand or none. So no, a credit card is not just a credit card and a debit card is not just a debit card. That simplification can happen at the 2.9% + $0.30 level, but many of the discounted rates get much more complicated with tiers for various cards -> You are extremely unlikely to get a 1% rate at high volume on a 1.25% cashback card for example.