Credit Card companies charge stores about 2-3% purchase value. Visa < Master < America Express. Some Credit companies give card holder 1% cash back because they earn much more money from the store. Debit card charges less one dollar per payment that it is why some stores ask limited spending value if payment by debit card. Some stores reject credit cards and don’t supply free plastic bags because they want to reduce cost and sale price. It is reasonable. If you don’t like it, you can go other store, such as Loblaws. I like Loblaws that food has good quality, environment is friendly and clear, but I have to pay much more money for those.
A few yrs ago I bought a car (new) in cash, the dealer only took my deposit by credit card, but when I wanted to pay the full price using credit cards, they refused to accept them and asked me to use the cetified check...
I think they just want to reduce the cost...Amex is not popular here in Canada due to high cost, even Loblows rejects it..