I would assume payment account in this case would be similar to eg a Paypal account. As in, they can obviously see the transactions you’ve done with them, and they will keep them saved, but I don’t see any reason why they would gather all of your bank account history
As someone who recently got a vasectomy at 27, I know how you’re feeling. I also never wanted kids, and have thought about getting a vasectomy from the moment it became legal for me. I still decided against it in the beginning, simply because condoms are easy and available, and I never really slept around too much. Then I met my partner, we talked about kids, and we both decided that we don’t want them, ever. So I had my vasectomy, and was recently cleared as sterile.
For me this was the perfect solution, as I never felt like I was rushing into something, I didn’t have to worry about what my partner would think, or if there might be a change in the future.
If you’re in Austria or Germany, Engelbert Strauss might be worth looking into. I have quite a few of their pants, long and short, and they’re all pretty great https://www.strauss.com/
Honestly, I understand that the opposite way. The payment account is still your wero account, that obviously has every transaction you’ve done with them saved, and not much else. Meanwhile the payment source would be your bank account, and they clearly state that they only save the account holder name (your name), type of payment source (presumably bank account, credit card, debit card, … in case they ever want to reach feature parity with PayPal) and a technical identifier, which would be your account number, card number, …, possibly (hopefully) hashed and secured in some way. I still in no way see any I dictation that they’d extract your previous transactions, or any transactions done directly from your bank account