Vault registration helps maintain the integrity of transaction signing and your overall multisig setup. It is a critical step that ensures proper communication between your multisig vault and your hardware device key. Registration is necessary in order to sign transactions with the following hardware devices:

Registration ensures that your device can only sign transactions for the vaults you've registered. This security measure, provided by hardware device manufacturers, prevents unauthorized use of keys and ensures that the multisig vault being signed is one that the device recognizes and approves based on the registered configuration.