PayPal does provide what is called "Guest Checkout" where buyers can use a credit card without creating an account or logging in. Depending on how your payments are integrated there are different ways to get this working best so that the Guest Checkout option is prominently displayed.
PayPal has Smart Payment Buttons now, which have greatly improved this process. They work with Express Checkout, and details about that can be found here:
https://developer.paypal.com/docs/integration/direct/express-checkout/integration-jsv4/.
The smart buttons include nice credit card icons, and when you click on a CC icon it gives a buyer experience that is expected for credit card payment without requiring a login. That's what I would recommend.
Angell EYE -
www.angelleye.comPayPal Partner and Certified Developer - Kudos are Greatly Appreciated!