Itch.io has two payments methods:
- .The developers handle the payments themselves - and I assume there might be developers who only accept one payment method, like PayPal.
- Itch.io collects the payments on behalf of developers and pays them later. I assume you can buy these games with the Visa card.
It would be nice if Itch.io showed that information on the developer's pages so people know that they're buying straight from the developer or from itch.io - but I don't think that feature currently exists.