Do any of you use high-interest savings accounts to finance your crypto purchases, or do you have to go through a traditional bank to avoid blockages? Thanks in advance.
Whether it's a high or low-interest savings account, so long as you have a card linked to it, you have the right to spend the money therein. And yes, high-interest savings accounts are doing the work in my country, but countries differ, and so is the ToS of the bank involved. So, instead of asking random people for a straightforward question, why not ask your bank directly? You might be shocked that it wasn't because you wanted to buy crypto, it might just be the random transaction failure, which often happens, even without valid reasons.
This is why it's good to have alternative card(s). However, if you must, why not try other means? Especially P2P. Except you do not want to use any centralised system, tere are many crypto exchanges in Germany, and I'm sure they offer bank transfer option, at worst.