Typically when using a credit card to pay on the Internet, you enter the card number and such in a blank text form. Here's a more fun form from a random airport wifi provider, where the form follows the layout of the card, including the security code on the back. Thus people who are less familiar with credit card forms can more easily make a connection. Us nerds are used to all sorts of obscure forms, but for people less versed with technology and online security this may be helpful. Plus it allows you to follow the groupings more logically in any case, entering the numbers as chunks of four (as they are also printed on a card), instead of a big 16-digit blob that you need to enter in most places.