lungeing a horse in figure 8

Question
hello, what is the advantage of lungeing a horse in figure 8? will this be applicable for all disciplines in English riding?

http://www.youtube.com/watch?v=Vf0dEXo4uMM

Answer
Pay no attention to this video.
This is not the classic way of lungeing a horse.

There are other videos I am sure which come closer to the correct way.
I hope to make one fairly soon.

The horse should be longed from a longe cavesson, regular web longe line, and longed in a large circle, eventually in side reins.

It is difficult for someone starting out in riding...there is much misinformation.