[alister]

At least in Brazil, it was very rare. In the last 3-4 years, it's almost every time you pay. And you have to grab and hold the payment terminal (especially if you're using tap / contactless payment) so the cashier or waiter, trying to be helpful, doesn't click the wrong button and cost you 15%.

[londons_explore]

> trying to be helpful

Some places they're insistent that you must do currency conversion or the payment won't work. Makes me think the merchant must be getting a chunk of that profit and telling their staff to accept the conversion...

[bayindirh]

Another more benign reason possibly be the customer's card might be closed to different-currency transactions.

For example, I can choose my bank to do the conversion at the time of purchase, or pay with that currency when the invoice comes.

[fn-mote]

> Makes me think the merchant must be getting a chunk of that profit Yes, they are. (No reference handy.)