I only came across this term recently. Wikipedia explains what it is quite well (https://en.wikipedia.org/wiki/Vocal_fry_register) and I came across this introductory video which uses it as an exercise (http://www.aussievocalcoach.com/2009/08/21/how-to-sing-vocal-fry/)
However I'm still not really sure of the point. Is it a register people use to extend their range downwards, or is it used as an exercise which will aid your normal singing range/tone? Because it doesn't sound very good to me!
What place does vocal fry have in vocal training and/or singing for a typical singer?