The payer couldn't care less about how much the store pays for the transaction. He or she just wants to tap with their phone, and the default here are Visa/MC cards. In addition to the transaction price not being an argument for the payer, Wero also afaik does not have as much consumer protection as (certainly some) credit cards offer. I also bet the average person doesn't understand or care about the whole political dispute either. Again, they just want to pay easily and safely.
I don't think Wero can "win" this from just the merchants side. It's got to be better for the customer's side.