Let's say, my current credit card is about to expire. I want to add details for a new one. The issue is that I have exactly the same credit card number but a different CVC and expiration date. In the first place, I cannot delete existing one and then add a new one. There is an error message. I am afraid that I will be not able to distinguish which one is the old credit card, and which one is new as I have exactly the same credit card number, but different expiration date and CVC code. I added a new credit card details on my billing page, and then was forced to take a look into generated DOM to find out the id of the card details and then just drop the youngest one.
I have a suggestion for you to display at least an expiration date as well on the billing page or implement functionality where I can edit my credit card details.