Now, YouTube videos aren't like DVD videos: they are compressed down to minimize the bandwidth so they can be shown on the web, even with a pretty low-speed internet connection. As a result, the video quality is less than a quarter of what you'll see on the DVD, and the audio quality is pretty rough, too - it sounds like the narrator is talking through a metal tube at the end of a piece of string.
Furthermore, you don't get access to the "customers only" web site that updates and enhances the video - information for accessing that is only on the DVD.
However, this is (it bears saying again) FREE.
We hope seeing the DVD on YouTube will help you see what the DVD has to offer and why it's worth $34.95.