they started off with stripe, and had/has all content behind paywall. no tour, no preview, no nothing, like traditional porn sites.
they kept it a secret from stripe while they grew, and thanks to using stripe, a mainstream biller, no one could compete with them. (as in paying out 80% to creators and still cover processing and costs)
stripe charges what, 4% or less? while adult billers are from 10% and up.
now they own the market, and i guess stripe turns a blind eye, because money.