Credit cards are not accepted everywhere in Germany. Generally we use Maestro debit cards. These cards are commonly referred to as EC-Karte. The system used to not allow touch payment, and is similar to a "chip and PIN" with debit VISA or Master Cards or credit cards.
Over the last years, supermarkets have started accepting credit card, and gas stations have always done so. But lots of smaller shops and many restaurants will refuse to do so because the fee they have to pay their card machine provider for using credit cards is much higher than for "regular" (Maestro) card payments. And even if they accept credit cards, many of these will refuse to accept American Express cards for their even higher fee.
I have encountered a few restaurants that make exceptions to the credit card rule if you convince them that you are a foreigner1 and therefore only have a credit card, because their machines are configured to accept them, but they have been trained not to let you try because of the higher cost.
Revolut has started to become more popular in Germany, although they to my knowledge don't actively advertise.
However with more German banks offering contactless with their credit and sometimes even their very new debit cards, the acceptance will likely go up in the future. I have even seen some BVG ticket machines in Berlin accept contactless, but couldn't use it because the reader was set into the same hole in the machine that also helps hide the PIN pad, and my phone didn't physically fit into the hole.
1) I am German but live abroad, and I still have a German card, but using my phone to tap is just too convenient and feels normal now