As a business owner, who accepts checks and charges fees for credit cards, I’ll take a check from a trusted party any day over credit cards when they want to avoid the processing fee, but I still have their credit card on file in case the check bounces.
edit: Further, it is a royal pain in the ass to accept a credit card payment, then have someone dispute the charge as if their card was stolen. The amount of energy spent taking checks to the bank is nothing compared to the energy, effort, and documentation needed to prove to a credit card company that the charge was legitimate, so you actually get paid and not take a total loss.
See my edit, and you are very far behind. Years ago VISA and MC (at least) specifically made it legal to pass along fees. A short internet search should confirm this for you.