“ known as an ‘interchange fee,’ from the merchant, roughly 1.5-3.5% of every transaction”

This jumps out because it is such a wide margin. In reality the average interchange fee is 1.8%. Amex at their _highest_ rate, which is the highest of all the networks is 3.5.

So “roughly” is doing a lot of heavy lifting in that sentence which gets further amplified later in the article when they use it to multiply by the total credit volume.

I don’t know that it fully discredits the argument but it is certainly a weak rhetorical tactic.

In the payments space margins are measured in basis points, 2% seems small to laymen. 200 bips seems crazy big to anyone in the industry.