I’d call that a minority, especially since Covid.
> not being able to pay with my card in a restaurant for example
An even smaller minority, especially for restaurants, slightly larger for non-chain fast food places that probably also cheat on taxes.
I don’t carry cash with me and pay almost everything with my MC debit or AMEX credit card, even in cases I can’t do that, I’d be able to pay with girocard (non-MC/Visa debit card, a widespread local system) if I had one.
Personal anecdote, but I've been travelling through Germany this winter and outside of motorway petrol stations and big supermarkets pretty much no one would accept my Visa/MasterCard cards - "EC Karten" only everywhere. We went to a big restaurant which I assumed would be ok because I could see the card terminal at the till, and at the end they told me it's EC Karten only - had to drive around at 11pm to find a working ATM just to withdraw some euro to pay them, while my wife and son waited at the restaurant - absolute nonsense.
It's been a few years since I've been to Germany, but for comparison, in Norway - while it's nearly unheard of now - you also used to be able to find places that'd take "BankAxept" bank cards, which would be pretty much every domestic debit card, and is similar to EC Karten, but not Visa Electron/Mastercard Maestro debit cards.
If you had a domestic debit card, you'd almost certainly have a Visa/Maestro logo on it as well and so it'd be easy for people to assume that was what they were paying with.
But from all the comments, I’m starting to wonder if SumUp had some focus on Lübeck and Hamburg for other places to not have the huge advances in card payments of recent years.
They only took cash.
Overall it seems more common than when I first moved here, but that's starting from a low bar, I'd guess going from 1/6th to 1/2 of the cafes and restaurants.