The advantages of a tool box truck bed cover go with out saying, however lets state the obvious. Many tonneau covers can not be install if you have a toolbox already installed on your truck. This is due to their need and access to the front end of the truck's bed. Tool box bed covers are designed to properly work with a tool box installed on your truck.
A great reason to have a tool box truck bed cover in lieu of just a truck bed cover is that you can still store all your important and expensive tools in a more secure structure like a tool box, while still protecting your cargo and materials that are stored in the bed of your truck. So if you are thinking about getting a truck bed cover or even just a tool box, be sure to evaluate your situation and whether you need a truck bed cover, a tool box, or both! Tool box truck bed covers are the best of both worlds.