I mean, in theory third party payment processors still take a cut. I don't think it's a dollar on a 7 dollar payment. But it's also not marginal.

The credit card companies themselves charge 3.00%+0.10 at the reasonable maximum (or roughly $0.31). That is still not even counting the payment processor's fees (which pay the credit card company's fees for you).

I mean the "7 dollar price" is all artificial anyway, it doesn't really cost Epic anything to make the product of those 7 dollars (it's economic rent extracted from the intellectual property they maintain). Either way Epic is making more money on this move even if the whole extra dollar is fees.