A payment flow of 'scan code, confirm in banking app' is hard to beat and we're 95% there. And all you need is your own banking app, no shady payment processors required.
You lose some stuff like the credit part of the credit card (although virtually no one I know actually uses credit, only debit cards) and consumer protections (chargebacks), but I don't think those outweigh the extra costs at all.
I still need a credit card when I rent cars and sometimes for online payments. That is an issue.