A practical application is to boost soft or weak sounds and to soften loud sounds with plenty of transients. Take for example an electric guitar or bass signal where normally not all the strings have the same output level, by applying some compression the musician or sound engineer could equilibrate the volume balance between the strings and make the overall sound more tight and consistent. Take another example, if you take a sound source of any kind that is subject of producing audio peaks of some sort, (for example a percussive sound with lots of transients) then the compressor if tuned right could smooth out the same audio peaks avoiding undesirable high volume kicks therefore making it more balanced in a mixing or live situation. As you can see there are some practical situations where the use of a compressor is a desirable and a practical option if not a true necessity at all.
The Compressor Box is fully automatable and has the ability to store 64 presets. It ships with a few already pre programmed ones that will show what its all about and may be the starting point to your individual creations.