The part for me where it breaks down is when you have to flip the card to the back to fill in the CVC. I also hate when fields auto-tab for me. Also, why does it hide the expiration date and name fields initially?
EDIT: And fill out the entire front.
By the way on the Mastercard on Chrome 28 on Win 7 it shows the CVC on the top left corner of the card so that the text overlaps with the border. On my Mastercard atleast the CVC is in the middle of the card.