Why do artist rarely use symmetrical balance in their work? what are some other ways artists can create a visually appealing composition?

To make it look clean, crisp, symmetry is really important because you do not want things looking uneven. Shadowing.

Because Having a symmetrical piece will not catch the attention as much due to seeming plain. the same reason you never have a centered human body in a video because if the image is off centered and not symmetrical it will have observers picture the story behind it and build up a story.
  

We need to see the sculpture