John Mueller recently confirmed the information that Google does not use links from YouTube in the search results. He announced this on Twitter.
One of the industry experts was asked:
I am the owner of a site with a lot of relevant content. Can I leave comments on YouTube videos using links to my site (subject to relevance, of course)? Will these links fall into the spam category? My goal is PR, but to draw attention to the site of users who can benefit from the content I recommend.
Müller commented on this as follows:
Google does not use YouTube links for searches, and YouTube users may find it annoying that your comments contain links to your site.