In addition to advertising through augmented reality, it can also be used to provide useful information to users.
For example, you could point your camera to a city skyline or some natural scenery, or a starry sky. The application can annotate for you all the important features of the picture. For the skyline, it could be important buildings. For the scenery, it could be important landmarks like mountains. For the starry sky, it could be the constellations and planets passing by.