There are 3 security mechanisms that prevent you from accidental loss or theft of your Bitcoin:
Two-part PIN on the Coldcard device
Seed Backup recovery codes
Wallet passphrases
If you lose your Coldcard
The Seed Backup allows you to recover your Bitcoin wallets
Your Passphrase allows you to unlock the recovered Bitcoin wallets
WARNING
Both the Seed Backup and the Passphrase are required to recover a lost wallet. If you lose the Seed Backup OR the Passphrase, you will not be able to recover access to your Bitcoin if you lose the Coldcard device.
If someone steals your Coldcard
The PIN protects unauthorized access to your Coldcard device, should it fall into the wrong hands.
If someone steals your Coldcard and your PIN
They will be able to unlock the device, but they will not have access to your Bitcoin wallets without the Passphrase
If someone steals your Seed Backup recovery codes
They will not be able to recover your Bitcoin wallets without the Passphrase.
WARNING
If someone has access to both your Seed Backup or Coldcard and its PIN and your Passphrase, they can steal your Bitcoin! DO NOT KEEP A COPY OF THEM IN THE SAME PLACE!