Bitcoins can only be transferred if you approve it with your private key; which the other party never sees. You can go lock the bitcoin private key up again, a

Bitcoins can only be transferred if you approve it with your private key; which the other party never sees. You can go lock the bitcoin private key up again, and not worry someone is going take more coins while you're sleeping. All that you have to trust is that the device storing your private key (hardware wallet, phone, whatever) isn't compromised. This also roughly applies to chip-and-pin systems, where the chip holds the private key. They're both like cash in a wallet -- giving someone cash from your wallet doesn't give them the ability to magically disappear more money while your wallet's sitting beside your bed later that night. Whereas with a (non-chip) credit card, once another party has your information just once, a theft can happen anytime from then until years later when the CC expires.