I read somewhere that the appeal at least in the designers eyes was because the lure stays horizontal like most of the natural foods.
My guess is that most jigs unless you had a a heavy body would hang horizontally.

In the winter( 40 to 50 degrees) we fish for crappie and gills with a 1/124 oz marabou jig suspened under a strike indicator. The retreve is slow strip and sit. We also catch the occational big bass this way. Its a killer!

We also catch trout this way if you match the color and size of the local minnows. We usually drop a small nymph 18 inches off the jig hook. The jig serves as weight and
catchs more than the ocassional trout while drifting and really shines when you tighten up at the end of a drift