> Apple doesn't charge any additional fees.

They do charge additional fees, just not to customers. Those fees get tacked onto the bank/merchant in the transaction. Apple charges between 0.15% to 0.30% of total transaction, according to Financial Times.

https://www.macrumors.com/2014/09/12/more-apple-pay-details/

No additional fees is not incompatible with getting a cut. e.g. they could take some of the card issuer's portion.