Earlier quoted context omitted.
> No not at all. No limits, actually only spending the exact amount with no way of spending more. Yeah you can do that exactly with a debit card - just ask your bank to remove the spend limit and give you zero overdraft. Once you realise effectively you are describing a debit card with less options then suddenly it doesn't look like such a good feature.
What kind of payment gateway are we even talking about? Are you describing "Sofort/Klarna"? I am not aware of any europe wide/international payment providers based on your bank account that does what you describe without basing on SWIFT and therefore being everything but realtime.
But now we are specifically just talking about international payments where you explicitly don’t want any currency conversion or buyers protection, and the use case is just getting farcically narrow.