In Germany being able to pay with a card is not a standard. And from that subgroup of places accepting cards, a big number of them will accept only Giro (German card standard). Visa/MC is far from being universally accepted and AMEX is even rarer.
That changes of course, but mostly in big cities' centers (Covid accelerated things in Berlin). I hope businesses catch up with the new wave of payment terminals like iZettle and SumUp - they support all these different cards without a problem
India, Malaysia, France, Switzerland and Germany. Go to small towns in most of Europe and you'll find a significant number of vendors not accepting Amex.
I know it is not accepted in many smaller places. I was reading maybe too literally the nonsense assertion, "accepted basically nowhere outside of the US."
Back when you needed to swipe that magnetic stripe the Amex one was different and required a special reader that almost no one in europe had. Except maybe tourist traps.
Not sure how it works now if Amex has discovered chips and contactless. The payment processors probably still need a separate path for Amex and I haven't seen that logo in a lot of places that do display visa and mc. So maybe it's still only available in tourist traps.
I gotta say MasterCard is pretty trash too. I was traveling in Japan and effectively unable to use my Apple Card anywhere because they only accepted VISA nearly everywhere.
Funny enough, loading money from my bank account into my Apple Cash which is VISA allowed me to use Apple Pay, avoid ATM fees, foreign transaction fees, and was just more pleasant than using my bank card.
I was there around the same time. I don't remember a single convenience store accepting Mastercard. And anywhere outside Tokyo or a major city you were unlikely to even see the logo. Cash only was certainly more rare than it was a decade ago.