Go to YouTube and type in Mentos and this went so viral through YouTube. I heard somewhere and don't quote me, I think the Mentos candy sales, because of the viral nature of everyone buying these Mentos to make these 2 liter Coke bottles explode, went up by 20%.
Absolutely, video very powerful to sell but you need a medium that people's eyeballs have to be on that video. Video compared to audio, if you had 100% attention of someone watching a video or demonstrating a product or just listening to an audio, video will win hands down.
But audio has so many other ways and opportunities to get inside the prospects mind from CD to listening while you are exercising, cleaning the house. You can multitask and listen to audio. You can't do that with video. You can't watch video in your car or you shouldn't be. So use videos to help sell and spread the word, but don't forget about the power of your audios.