Even more strange, Berlin (and perhaps much of Germany, I don't know), places much greater emphasis on cash than on electronic payments like credit cards. I gave a credit card to a vendor once and they looked like they couldn't figure out what it was. In fact, as they were trying to understand it, I motioned that they were in fact studying it upside down! Other restaurants would tell me it was the first credit card they had seen in weeks, and the owner simply hadn't bothered to bring the credit card machine in from his house in a long time. Not a problem, just a bit strange to me.
Berlin is a neat place, though, and I love German food (and beer) a lot, but it cannot be overstated how you quickly come to realize that you currently take for granted speaking the same language as everyone around you, and unless you know German already, that convenience will evaporate immediately upon moving there. Even all the Holywood movies and U.S. TV shows are dubbed into German -- it is the largest overdub market in the entertainment industry, because Germans generally place low emphasis on learning other languages (just like Americans do).
The only reason to have a credit card as a German is for buying this outside of Germany.
Credit cards aren't any more popular in the UK, but our debit cards tend to be Visa/Mastercard and we use them the same way. I think mainland Europe has some catching up to do to London as far as being a cashless society :)
I would say the opposite is true: If you need Visa/Mastercard, your country's banking system is broken. Sending cheques via physical mail is something nobody would even think of over here. I think I have never even seen one.
Amazon.de e.g. offers the choice of * credit card (as internationally) * direct withdrawal (meaning you give them your bank account details and they withdraw the amount directly - sort of sketchy from the customer's point of view, but no different from credit cards - if anything goes awry, you just challenge the charge directly with the bank instead of the card issuer) * bill-based (generally only for small amounts or trusted customers - might involve a "credit score" check from Schufa (https://en.wikipedia.org/wiki/Schufa) to deter fraud)
I agree with everything you say, except that. Older people form Eastern Germany obviously did not learn English in school.
In Germany it is not like the Netherlands or the Nordic countries, but I would say in Western Germany you have a much higher chance to meet people who can speak English or French at a decent level than you have in France or Italy to find someone speaking English or German. And that is inspite of the German market being much bigger and people from Eastern or Northern Europe also often being able to speak German.
Of all highschool student exchanges to France or Britain I know of, the students ended up speaking the other language, not German. I remember a neighbour had an exchange student from England over at his home. He supposedly learned German in school, but just repeated his sentence "Um 5 Uhr fährt der Zug nach Berlin.". This really changed my perspective on the foreign language education in Germany.
The start-up scene speaks English fluently and buying stuff etc. doesn't need much talking.
The start-up I work with has 2 employees who don't speak German at all and they say it's only a problem when they are in smaller villages.
If you want to incorporate a business, you do not necessarily have to do it in Germany, it is the EU after all.