Well Youtube is appearing everywhere - on Google searches (there's a video column which lists a lot of YT videos, or videos from other video sharing sites). So building links to the YT page can help you increase your ranking for specific keyword searched on Google, for a specific video, etc. Previously YT was an authority site on Google, whereby most searches would point to a YT column, but they have since adjusted that. Nevertheless, if you are able to point quality links to the YT video page, that should increase the SERP for that video on Google.