The page http://vitalcoaching.com/cheatingformen.htm got around 512 visits and made 10 sales in 4 months
the conversion rate is quite high compared with other pages and especially considering the fact that the sales page is almost only a video.
On top of that the product is one short e-book only!
This proves that video does sell pretty well!
maybe 50% of traffic originates from youtube.
That's not much but indicates a traffic building + selling that strategy that works for that specific e-book