Switzerland has interchange fees of 0.4% for consumer credit cards (by contactless, only slightly higher by chip+pin): https://www.visaeurope.ch/content/dam/VCOM/regional/ve/unite..., https://www.mastercard.com/content/dam/public/mastercardcom/.... And yet banks offer 0.33% cashback cards: https://certo-card.ch/one.

And let's not forget that cash acceptance costs an order of magnitude more than this anyway; if anything businesses should charge surcharges for accepting cash, not the other way around, and given the social constraint of no surcharges, cashback is a fair mechanism to reward efficient payment methods.

> Switzerland has interchange fees of 0.4% for consumer credit cards

Only since Wednesday of this week due to COMCO action, so no-one knows if cashback will persist, but it will be a lot less than .33%.

> And let's not forget that cash acceptance costs an order of magnitude more than this anyway;

In the EU, it's .5% for cash vs .3% for cards, but the situation falls back into favour for cash once fraud is accounted for.