Practicing in front of the mirror with other instructors help with 70% of your skills. But while practicing your mind is focused on what move is coming next or what cues to give. Plus you can only reliably see yourself from the front.
When watching a video of myself I cringe everytime I make minor mistakes! And I go, "Why didn't I catch that?".
Watching a video playback allows us to critique ourselves better, and see ourselves from a different angle (if we place the camera off-center). Highly recommended for everyone!
In fact, thinking of getting a video camera just to video myself frequently!