They most likely don't charge fees on consumer.

Usually the fee is on merchant (and it's few % depending on region regulations etc.) Payment providers such as Wero are doing direct bank transfer, which is usually fee-less, but then they can afford to put a on-merchant fee that's much lower than what credit card companies are charging.

Thus the model is win-win-win: Consumer doesn't pay more, Merchant pays less, and Wero gets their share.