how about risk management? when i pay using a credit card, i know if things go sideways i can always dispute and most likely will get my money back. If I pay with bitcoin or even with cash or checks, i'm fucked. Not sure if Visa/MC duopoly specifically is the most efficient way to handle this risk, but it is a thing.

P.S. also too not sure how special credit card hardware is a problem anymore, if you want to pay with your phone, there are more and more options every year to do that, and even tie that to a credit card (for benefit of risk and/or points).