

Remember that Discover is self-banked (unlike Visa/Mastercard that banks sign up with). This means that every credit line needs to be backed by… well … A bank.
Bigger banks mean more credit opportunities, better interest rates (etc. etc). Deeper credit lines.
Itch.io is currently saying the problem is Stripe, and maybe Visa.
Historically (ex: https://otakuusamagazine.com/visa-and-mastercard-refuse-to-work-with-another-doujinshi-retailer/), I’d say Mastercard and Visa are both to blame. But the jury is still out on wtf is going on here.
I’m not sure who pressured Steam. But Itch.io (https://aftermath.site/steam-itch-porn-censorship-collective-shout-visa-mastercard-paypal) is claiming Stripe and Visa are pressuring them.