PayPal and Apple pay take a significant cut of the transaction. CC is a lot less and bank is mostly free of TX fees.
Most users don't know/don't care, so given the option, they will likely take it and funnel their donations to conglomerates.
This site does use buymeacoffee.com, which appears to be a dedicated payment platform. Its transaction fee is apparently 5%, which is steeper, but better for these small donations because of the lack of a fixed fee.
I believe there are other services that will also give you virtual cards, I'm not familiar with them off hand.
I don't think this is true
> Apple Pay does not cause additional fees for users and merchants.[1]