From Google Webmaster Central, just in case you missed it:
Help Google index your videosQuote:
The single best way to make Google aware of all your videos on your website is to create and maintain a Video Sitemap.
I was reading up on this at the link that you provided and it seems like the description tag is pretty important for SEO. It looks like you have a limit of 2048 characters to describe the video. There is also the video tags that you can have up to 32 tags.
It seems like another opportunity for us to do some SEO if the following is beneficial (taken from the comments on that blog):
"The video sitemap will point to the url where the video is located on your site. So, if you posted a video on mysite.com/embedded-video.html the sitemap would point to that page on your site."
So I think the implication is that a search for a video may lead to one of our video site-mapped pages if we optimize for this.
I am tending to embed videos in my blog posts so this is an exciting development I think.