Yes this is definitely an extra layer of safety. Essentially, you get two attention systems to get you where you’re going. If the backup system fails and the driving system recognizes that attention deficit to stop and alert, you’re safer than if you only had a sleepy driving system.

Tesla auto steering disengages for the ride, and you get several strikes until it turns off for good without recourse, if you’re inattentive while the mode is engaged, and you need to touch the wheel quite frequently especially at night to confirm for the legal requirements, since the interior cam can’t see you clearly. I hate to have to pull the wheel slightly so frequently when it gets dark (when wearing glasses).