I have found
auto paint to be really durable and easy to apply.
DON'T DO IT! Or, if you do, be careful. (I am assuming he means enamel, btw.) Enamel takes a long time to dry/cure. If you DO use enamel, BE PATIENT. Wait DAYS before you bolt the guitar back together. Otherwise, the enamel may still be semi-liquid, and you will get all kinds of ugly "pushing" of the finish when you bolt things like the bridge, neck, even the pick guard back on. I know, as I am currently refinishing a Mustang copy someone repainted in enamel, and got impatient.
And do know, auto-parts store lacquer is NOT NCL. It's ACRYLIC lacquer.
If you make mistakes, get dust in the finish, etc, lacquer is easiest to fix, followed by enamel. Poly is pretty much unfixable- mistakes either live there forever, or you take it off and start over again.