Every choice you make in creating a quilt is 'fair game' for judging. The design, the color and fabric selections, the thread, the quilting pattern, all of it. It's far more than simply the workmanship, it's the final combination of correct choices made by the quilter...that's what is rewarded.
If you create a quilt from a kit, the choices have mostly been made for you. Even using a pattern, you are making fewer decisions than someone who creates a quilt of their own design. It's like going through a maze. If you had to make twenty correct turns to reach the end, shouldn't you get a bigger treat than if you only had to make seven?