> The card is a physical representation of your account number, readable with a magstripe scanner.

Which is no longer true for EMV cards, though. There, the chip contains some additional data which cannot be easily copied and which helps identify the card as a bona fide real card issued by a bank.

https://www.emv-connection.com/contact-chip-card-online-auth... (there's also some alternative authentication method that would work offline, i.e. just between the card and the payment terminal)