Ah see though it can be used for more than what I did (actually, haha I have never done a dubstep song in my life I just know how to do stuff and made the video).
Say you have a blast beat, which has a snare that is hit softer by nature but you still want to hear it at that part. You can automate the gain to increase durring that part so you can still hear the snare.
Some other things I have used it for was to turn off the reverb on something so the tail didn't ring out during a quiet part. I've used it to make the entire song intro sound thin and then had the eq drop off so it came in full freq spectrum.
You can do a lot with it, it's recognizing when it's needed that makes it hard to use. haha