I would have thought you need to be low margin to care about this, or exhausted all opportunities for growth and cost savings.

And even then it is risky to lose a customer by refusing or not offering credit card options.

If you offer both CC and transfer it’ll be like $9.99/user-month for CC and $9.81 if you pay by transfer so it is not too sexy a saving for the customer.

I like what you are doing but I wonder how you get a foothold on it. The “using CC but hate the fees” niche must be small because they are already using bank payments if they need to. For example an employee or freelancer or company that does large yearly payments.