They do the same for US cards. EU regulation states that you need to at least give this choice for a consumer, and they cannot force you to take bad exchange rate. If I recall correctly EU might have given a slap on the wrist for AirBnB, as an US company, for not complying with this and forcing to pick bad USD rate. (I do not have source now, on mobile). So overall I think we can agree EU system with regulation is vastly better and less crooked for anybody else expect card issuers and payment processors.