[mtmail]

Nobody but the most secure payment providers store credit card information. The legal requirements and implications are so big you never want to have credit cards touching your systems directly. Think about storing private healthcare information, the credit card industry is in some respects even more strict. https://en.wikipedia.org/wiki/Payment_Card_Industry_Data_Sec... I'm not even sure if you could get business insurance, mine forbids dealing with credit card data.

> However for people who just check out with their credit cards

There are plenty of solutions by the various payment providers, e.g. https://stripe.com/docs/payments?payments=popular ranging from buttons that open a new webpage (on the payment provider domain) and return after success to iframes that look like your own website but securely transfer input to the payment provider's systems. Paypal does ask the user to login but I think that's optional. Stripe doesn't have user accounts so Stripe doesn't ask users to sign in.