From the webpage:
In order to deliver search results, Google crawls the web and collects information about each piece of content. Often the best results are online videos and Google wants to help users find the most useful videos. Every day, millions of people find videos on Google search and we want them to be able to find your relevant video content.
Google is supporting schema.org for videos along with alternate ways to make sure Google can index your videos.
It is a fairly coarse start but beats no information about your videos at all.
Videos that can be easily found are more likely to be incorporated in topic maps (and other finding aids).