The merchants never pay, you do: prices all increase by exactly 3%. You think employees accept a 3% salary decrease because suddenly all clients pay by cash ? A

The merchants never pay, you do: prices all increase by exactly 3%. You think employees accept a 3% salary decrease because suddenly all clients pay by cash ? Absolutely not: prices will increase to cover the risk of this happening, and neuter the cost of the payment processor: it's one more cost, and you are the one paying. The merchant RECEIVES your money. He will not OFFER anything to you or the payment processor just for the sake of it.