Beware of paying for foreign transactions with US dollars
Though there’s a smaller fee for paying in US dollars, you might not actually save much, if at all.
When you buy something from a foreign merchant, the clerk may ask you if you want to pay in the local country’s currency or US dollars. If you choose the latter, the merchant will convert your bill through dynamic currency conversion.
This can add a significant markup on the exchange rate, and you could end up paying more than if you’d just eaten the 3% fee.
Of course, you can avoid all this using a card with no foreign transaction fees.