A rack is important in that it allows you to easily roll your shrink wrap over your project. This is important, as it helps keep the shrink wrap clean for the best durability, as well as for the best adhesion of pleats, adhesion of tape for shrink wrap access doors, adhesion of tape patches, and adhesion of adhesive backed access zippers (un-shrunk shrink wrap film has static cling so dirt will easily stick to it).