"Store cards in phone wallet to prevent theft The video explains that when you add a physical card to a mobile wallet, your real card number is never transmitted or stored on the device, removing the most common attack vector for fraud. As the narrator puts it, "your real card numbers aren't stored, so they can't be stolen. And even if you lose your phone, your card is safe, protected by fingerprint or facial recognition." This means switching from a physical card to tap-to-pay on your phone is not just a convenience upgrade — it is a structural security upgrade that eliminates the risk of card-number skimming entirely. Someone who acts on this lesson moves from a system where their number can be copied to one where it never leaves a secure enclave. Source: Derek Muller, Veritasium, How Your Credit Card Works — and How It's Being Hacked"