It does not directly answer your question, but many (most?) merchant agreements in EU have significantly higher fees for accepting non-EU cards. E.g. Stripe tak

It does not directly answer your question, but many (most?) merchant agreements in EU have significantly higher fees for accepting non-EU cards. E.g. Stripe takes 1.4% vs 2.9% for EU vs non-EU (card-present EMV transactions are typically much lower cost, but that still shows the idea).