If you are starting applications from the notification bar (by using another app, like Notification Launcher), you will notice that some of them do not offer a link to default home/launcher. This app bridges that gap by providing an app and an icon to add to the notification bar in case you want to go to your default launcher that way, avoiding pressing the hardware button.
Apart from this, the behaviour is exactly the same as pressing the physical Home button on your device. If you do this n times a day, you might appreciate the idea.
