Why download videos from youtube? There are several reasons. Either to watch the videos offline or to collect them. Watching offline generally results to the limitation of internet connection. If the video is instructional, you would want it to be played over and over again. Some do for the karaoke or videoke songs they can follow offline especially if they are practicing for a singing contest. Other do not want their movie-watching hampered by waiting for the next part to load.

How do you download the videos anyway? With Windows, you need a software to do it. With Linux, though, youtube video download is easy as playing it online once and get the copy from the browser cache.