When the search engine spiders crawl through a webpage and see a <video> tag they think, "Ha, a video!" and move on none the wiser.
This widget changes the ball game as it encloses the video in an HTML5 figure element.
Inside this is an h1 heading and a paragraph to describe the video content. Now the spiders have a name and a description for the video and are very pleased.
The humans will benefit from this too!