I have had a lot of success with video email. I get a lot of WOW responses, I think just for the general fact that they rarely get video emails from anyone else. From a business perspective, I see the highest value of video email in new introductions. It's very hard to make an impact in one email with new introductions so what I do is send a video email. This allows me to get my personality, body language and other positive traits found in face-to-face communication that otherwise would be lost in text email.
The shear fact that you are doing a video email shows you are vested in the relationship. Most people won't understand actually how easy it is to do it, but they don't need to :)