Comment is a way to interact with viewers and to know their minds on the video. More comments on YouTube videos means more engagement of people in your video content. It indicates that video is getting attraction of peoples as they can’t live without putting their two cents on the post. Wait… one more thing, positive comments brings you more visibility in search results even though if you are enjoying good number of YouTube Likes your video will get preference than other videos in your niche.
One more thing it can bring massive traffic to the site also if you have many videos with more views, comments and likes.