For instance, they might allow you to download entire playlists, rather than individual videos one-at-a-time, and converting these to MP3 with a single click of a button.
The YouTube Downloader desktop software generally provides more functionality and power than web applications. You can have up to 30 download threads running simultaneously, although depending on the speed of your processor and the bandwidth of your Internet connection. With Free YouTube Downloader you can easily download YouTube videos and convert them to MP3 or MP4.