I used a rollbar in my Ranger for hauling carpet to job sites.( Flooring installer by trade. ) Thought that a rack would work well on my F150 for the same thing. Although , I don't haul as much anymore.
A lot of guys put lights on top too. Usually see them on construction or ranch trucks. Keeps stuff from coming thru back of truck in a emergency stop situation.
P.S.: HAPPY NEW YEAR TO ALL!!