Since macOS 10.9.4, Time Machine sets the attributes of the partition on an external backup drive so that only macOS and Time Machine can modify the drive, with users having read-only access (see here).
Bitdefender describes the Time Machine protection feature as an “extra security layer” and a “complex feature” that “gives you the edge against any malware that tries to encrypt or destroy your backups” (see here).
Thus, what precisely are the additional benefits provided by Bitdefender, given that macOS already protects the Time Machine backup drive?