Could anyone explain why the bolded part of the wrap key description?
Wraps a symmetric key using a specified key. The WRAP operation supports encryption of a symmetric key using a key encryption key that has previously been stored in an Azure Key Vault. The WRAP operation is only strictly necessary for symmetric keys stored in Azure Key Vault since protection with an asymmetric key can be performed using the public portion of the key. This operation is supported for asymmetric keys as a convenience for callers that have a key-reference but do not have access to the public key material. This operation requires the keys/wrapKey permission.
AFAIK, all the keys in Azure Key Vault are stored at rest in HSM modules. Why is key wrapping necessary for symmetric keys? What does ‘protection’ mean in this case? Using a public key to encrypt data?
If HSM are securing all the keys in Key Vault (using its built-in symmetric key), then why would encrypting a symmetric key be necessary as quoted?