Trite comment. Debit/credit cards never took off in Germany because everyone had a Giro card that worked perfectly well for cashless payments. And for online payments, PayPal filled the gap quick enough. The average German saw no reason to request a Visa/MasterCard from their bank for a heavy fee when PayPal did the job. That's also the difference: Germany never had the "Here, have a free credit card" culture.
With a more benevolent reading of my comment you could have seen that I do consider them equivalent for cashless local payments. My first sentence was meant as "[American] debit/credit cards". This doesn't invalidate anything I said.
