Germany actually uses their own card system .. or cash. They are very much against visa/mastercard due to their “high commission fees” and “privacy concerns”
You're comparing a regional debit network to an overarching network that includes lots of different fee structures. The USA has debit networks (STAR, etc) with similar cost structures too - Germany is not unique in this regard.
That's somewhat outdated and Wikipedia even slightly alludes to it with "Some banks are phasing out girocards". "some" in reality is "nearly all". Girocard is practically dead and I don't see it coming back without state intervention.
There's a few holdouts in stores here and there that only accept Girocard and no other cards (my vet for example), but it's on the decline there, too.
"Privacy concerns" won't hold out long against relentless pushes for more deregulation of privacy laws for AI/other tech/"the economy"/etc and removal of data access hurdles for police/security services/etc coming from certain political spectrum - whose voters generally don't have high concern for such fundamental rights issues when at the ballot box.
Unfortunately, that's not enough to shake the MasterCard/Visa stranglehold. Even if all of Valve's German customers used Girocard and Steam sold those particular games only in Germany, they would still have to yield to pressure from MC and Visa because losing them would cost them many more of their global customers.
It's not enough to simply have an alternative to the credit cards, that alternative has to be in the pockets of 90% of your user base before you'd be willing to lose the method of transaction they currently rely on.
> Payment service providers shall not offer or request a per transaction interchange fee of more than 0,2 % of the value of the transaction for any debit card transaction.
So does Russia, Denmark, Belgium/Netherlands, Iran, China. I’m sure there’re others. I know someone working on unified payment platform for games in Africa. They have dozens of different payment systems instead of the two.
Girocard charges a 0,3% fee vs visa/mastercard 3%
See: https://en.wikipedia.org/wiki/Girocard