I have to second damnimissed comments. Its not ALL about the look, but a nice looking jig instills more convidence in the fisherman which makes you a more productive fisherman.
In my experience, probably 2500 jigs poured, painted, and fished over the last 10 years, the powder paint is the quickest, easiest and least messy way to paint jig heads. A properly cured powder paint head is pretty good.
That being said a properly painted jig head using vinyl jig paint is almost indestructable. People like to talk about how tough their powder coated jigs are by dropping them on pavement. If you do a primer coat, one or two color coats, and a top coat of vinyl paint (yes its stinky, kind of messy, and time consuming) you can throw it at a brick wall as hard as you can and it won't chip. This is because it dries into a very hard yet rubbery finish which aborbs a lot of shock and abuse. Powder coat dries hard and brittle so it will eventually crack and chip.
And yes, a top coat of pearl white or pearl pink vinyl paint over any color looks amazing.