Existing online services don't generally give you a lot of choice for payment.
"No other choice" != "Like".
Credit cards and bank transfers (which in Japan are very simple) have different strengths, but the one that sticks out for me is that a bank transfer keeps more control with the buyer, and exposes the buyer to less long-term risk: The service provider can steal your money by not providing the service, but they don't have any info they can use to steal money in the future.