> It does not make sense (to me) to say that you use dollars to buy a big mac in Paris. You use euros, which your credit card company conveniently bills from you as dollars.

I see your point. To be more precise I use the MasterCard payment network that uses a combination of Mexican Peso, USD, and EUR in the background to settle with the merchant’s bank periodically in the background (and as I use Revolut based Mastercard, it’s even more complex).

Last month the biggest POS company integrated the lightning network, an international payment network protocol, that uses Bitcoin as its settlement currency and Bitcoin network using Strike, and as the POS company does the settlement with the credit card company, the merchant in practice doesn’t see the difference between accepting credit card payment or lightning payment, as it doesn’t handle any of the two (the POS provider handles them).