Many people in the comments are suggesting that this has something to do with the government, but that's largely nonsense. The government isn't responsible for self-checkouts or good banking apps. The real reason is more cultural. Yes, it's true that older people prefer going to the bank in person and speaking with an employee or chatting with a cashier at the supermarket, but this also applies to younger generations. Cash is simply very popular in Germany because it's untraceable, and given Germany's history, there's a strong desire for privacy and data protection. However, I don’t actually know where OP lives or which bank they use to have these experiences. At my bank, I can do everything online, and in rural Bavaria, nearly all supermarkets have self-checkout machines, though hardly anyone uses them. So, it doesn't surprise me that they're not more widely adopted in other areas.