In many countries it's illegal for shops to either not accept cards or to charge more for card payments (even though they do cost more, more than 5% of the transaction cost in some cases). I think this measure of hiding away the real cost of card transactions was the main driver for increased usage in earlier years.

In Europe card charges are capped at (IIRC) 0.9%

Interchange fees are capped at 0.2% debit, 0.3% credit. Somewhat higher (~1.2%) for business cards. These caps do not apply to cards issued outside the EEA, nor do they apply to three-party networks such as Amex.

Despite that this displeases the networks, businesses are allowed to elect to only accept a subset of card categories (i.e. they may decide they accept Debit Mastercard only, not Mastercard Credit or business cards). That said, honor all card rules _within_ a given category have been found enforcible (including that e.g. a merchant can't decide they accept Visa Debit, Debit Mastercard and Mastercard Credit but not Visa Credit - Visa are allowed to say "If you accept Visa Debit and Mastercard Credit, you must also accept Visa Credit")

Processors/Terminal providers will add their own margin on top of these, of course (interchange fees are entirely remitted to the card isssuer)

> They do not want to share their very thin profit margin with the electronic money vendors.

Then they are quite possibly operating with a false economy somewhere, due to the costs associated with cash handling.

Of course it helps to be in a country where card fees are capped.