A lot of what you talk about is very basic SEO.
The description mentions the keywords multiple times as this tells both YouTube and other search engines what the video is mainly about. This is why it is important to have your keywords in your description more times than any other words. Of course, don't just list them, as that is against YouTubes terms.
If you have ever created a website, it is exactly the same thing, you want your keywords to me prominent as that is what the search engines will pick up on.