I'll chime in. First off, this program does require some knowledge before you go crazy with it. Right now, most people are using ATR to set up your launch control and flat foot shifting, which is a very simple thing to do. Others have adjusted their idle speed, so that if you have a motor mount or TMIC, the vibration isn't as bad.
If you take the time to read the book, or at least the first portion of this, you'll find some other tools to help improve the way the car runs. Calibrating the MAF sensor is another common activity, and it improves the fuel trims and helps calibrate your car to your particular location.
In short, you really don't need to use this at all, you can run with the maps Cobb is providing, but if you want to take it to the next level, this is the way to do so.
