Think about this for a moment from a merchant's perspective:

A customer is ready to pay. They hand you a Visa. You know there will be some "discount" taken by your bank, but you don't know how much, nor will you know until the end of the month, well after the fact.

Do you ever not know what something will cost when you commit to a transaction? That's the way it is all the time for merchants with credit cards. Seems nuts to me.

Would you eat at a restaurant, sign for the bill with a range - your dinner cost $90 to $100 tonight. We'll tell you how much in a month. And then you can't say anything about it.

These companies have merchants in a very awkward position.