You're at the airport, ready to head home after a couple weeks in Italy...or wherever. You have some leftover Euros. What do you do with them?
You could bring the Euros home and use them next time.
You could buy something at the airport.
You could find a chain coffee shop, like the one you have back home. Buy a gift card with the exact amount of leftover Euros. Whatever it translates to when you get home...it's a cup or more of coffee.