If you turn off the sound when watching a magic video you can focus much better on the handling and flow of a performance and on the clarity of the effect(s). Let’s call this the Méliès Method, in honor of that great pioneer of movies and magic, Georges Méliès.
As a spectator, it will become abundantly clear to you that too many magicians fumble and gesture far too much, particularly with a deck of cards in their hands, which magically seems to keep them twisting and turning, tapping and pointing, riffling and ruffling.
As a performer, watching yourself in a silent performance mode can help you tremendously in streamlining your presentation and in cutting out loads of unnecessary and unpleasant hectic or distracting gestures and movements. Give it a try!
On the other hand, if you want to improve your script (and who doesn’t or shouldn’t?), you may want to focus only on the sound of a taped performance and refrain from watching it at the same time.