It’s more likely to replace the 3-digit security code that you have on the back of the card for online purchases, right now, if someone intercepts your credit card number, expiry date and that 3-digit security code, they can buy any stuff using your card. This solution would make online credit card purchases instantly secure. And for in-store purchases it could replace your pin code so that you do not need to trust the little merchant from not stealing your pin code, it’d be a one-time small purchase pin code for that kind of use. For withdrawing cash from the cash machine, you’d still need your own secret pin code.