The most common use for Headset Menu, of course, is setting applications like Google Music or Spotify to open when headphones are connected, so you can listen to music immediately. But of course, there are many other interesting ways to use it.
Headset Menu users can also activate a small menu of selected applications to be deployed when headphones are connected. In this menu, you can put icons to your preferred apps for listening to music, YouTube, your favorite game, and so on.
Headset Menu is a very simple tool that will save you a few seconds every time you connect headphones to your Android device, which is probably quite often.
Requires Android 4.0 or higher