Let's look at the real life scenario when a merchant tries to sign up with a local bank to accept VISA. Trust me, I've worked on this in real life:

Merchant: I want to accept VISA to help my business. Can you help me out?

Bank: Great decision! Here's what we have blah-blah-blah

Merchant: Ok. Sounds fair.

Bank: Oh, have you considered you may have foreign customers?

Merchant: Hmm, never thought of that

Bank: Well, you should in this global economy. The reason why we say this is because we have an agreement with VISA to allow customers to choose their home currency at the point of payment. So let's say an British tourist comes into your store and he uses his VISA card issued in the UK. Our machines, with our exclusive deal with VISA, allows us to show them their amount in British Pounds. It's called dynamic currency conversion and it's another level of service to help your business. (conveniently omits any discussion about the details of DCC and how it really doesn't help the British tourist)

Merchant: Oh cool.

Bank: We usually charge a fee for this service, but since we like you so much, we're going to actually give you a substantial discount on your fee for this if you agree to stick with us for [insert some contract date range].

Merchant: Sounds like a deal to me!

Bank: It definitely is! (for us!)