Generally, spinnerbait rods will have a softer tip (correct me if i am wrong), for making very accurate casts. Jig rods are a bit stiffer and heavier duty to get fish out of heavier cover. You could fish spinnerbaits on a jig rod, or jigs on a spinnerbait rod, but if you were to do this, you would hook and land more fish by compensating for the action of the rod by tightening or loosening the drag, or by using a line with more or less stretch, depending on what you are using that rod for.