[karottenreibe]

The reason cash is predominant in Germany is not privacy concerns but horrendous fees for every transaction for smaller shops like bakeries. So the small shops often enough don't offer card payment that you simply have to keep cash on you. I have never met anyone that payed in cash because they want the privacy it offers. Quite on the contrary: people regularly complain about having to pay in cash.

[Tainnor]

Add to that a lack of "customer service" mentality (i.e. I don't care if I have to send the customer to an ATM) and probably a healthy dose of tax evasion.

[lutoma]

At least where I live almost all bakeries have added card payment as an option during the pandemic. So clearly it's financially feasible to at least some extent.