Whenever you see a coated mast with chipped paint, you know that whomever did it did not put on the bright yellow Zinc Chromate (I think that is the correct compound -) primer. Paint doesn't chip with that stuff on.
As for painting, it does make it look better, particularly if you have screw holes that have been filled in and if your mast was like mine - weathered. It makes the whole rig look a lot spiffier, IMHO.