As a contractor, I also get paid via a bank transfer (through Wise, which handles the international part). It seems weird to me as an American, but I guess it's just normal in the EU.
- normal credit/debit card, which can go through all sorts of different "middlemen", US or European based depending on the site
- "immediate" bank transfer, which is still integrated into the payment flow and provides confirmation straight away, and is usually handled by the Swedish/German middleman Sofort/Klarna
- suprisingly still very common, at least here in Austria, is the "send me an invoice" option, even for physical goods that are being shipped, then the customer makes a manual bank transfer after the goods have been received
Sometimes it's also about what systems customers are used to, or fees with each method.
If bank transfer is the only option, it's usually for businesses that payment providers won't touch (even if not illegal).