Asphalt Based Undercoating does provide some benefits over Waxed Based Undercoating. They both stick well to most any surfaces and do a great job sealing out moisture, road chemicals and oxygen. But mainly, Asphalt undercoating has the benefit of being less expensive. They protect anywhere up to 5 years and dry to a Firm to Hard coating.
Asphalt Based Undercoating does require a thicker film thickness meaning you will have to apply more product to the surface to be protected then if you use a Wax Based Undercoating. Additionally, Asphalt based products require more surface preparation because they can actually seal in rust and moisture allowing it to continue to grow. Finally, Asphalt based products continue to dry out over time causing cracks in the coating surface.
So, if you are looking for a more cost effective undercoating that can protect your vehicle for up to 5 years but may require a little more surface preparation… then Asphalt Based Undercoating is what you need.