> The important thing is not what merchants want, but what customers want.

What many people in Germany want is a payment system that is as anonymous and is as hard to control by some untrusted entitity (both government and banks are very distrusted) as possible and what cash offers. That's basically cash.

Not without reason, in Germany there exists the well-known phrase "Bargeld ist gelebte Freiheit" ("cash is lived freedom").

Agreed. Customers are benefitted either by paying in cash - for the reasons you described - or by paying with cards, for fraud protection and the ability to make purchases online.

Any other payment method will not give customers any benefits over those methods. Unless banks are willing to take responsibility for fraud like with card purchases.

Would this work? https://en.wikipedia.org/wiki/GNU_Taler