High retention time on your video can provide the growth of ranging in the YouTube search. This makes your video visible and recognizable for more people!
The more audience engaged and interested in your video - the more view hours are provided for your channel. Popular channels and videos are shown in the search and offers for the viewers much more often. Become popular for your audience!
Find your regular viewers using this service, and other people will be subscribing and watching because of the high interest in the channel! YouTube will recommend your channel more often and, therefore, more people will find out about you and your videos.
Like is similar to the the applause for the video. The more likes you have - the higher popularity you get. Your target audience will find you much faster, because the ratings of other viewers are always trusted.