Cards on an Apple Watch are provisioned separately from those on a paired phone. They have different card numbers, and are provisioned as two separate passes,

Cards on an Apple Watch are provisioned separately from those on a paired phone. They have different card numbers, and are provisioned as two separate passes, each with its own fraud control. Once a pass has been added to one Apple device, a reference token to that physical card is added to your iCloud account, which can be used to initiate the provisioning flow on other devices. Usually that token requires at least a CVV to prove possession, but may also require bank-issued OTP or phone call verification as well. The Secure Enclave is small, but supported between 8 and 16 cards, depending on hardware. As of iOS 17, the atorage is based on actual space available and can store upwards of 30 cards on an iPhone 14.