Having roller installed (it was actually already fitted when we purchased the camper) is a benefit, I did have a massive OH-OH moment one time in France where I thought that did not sound good, the roller stopped the erse end from I reckon would have been severe damage to bottom rear panel.
The outriggers which support the rear bump bar and roller is fixed to this where outriggers cantilever under and out to the rear of the camper, it has been well engineered prior to fitting.
The roller is assisting along with camper rear suspension, basically stopping the suspension bottoming out, and if there is an OH-OH moment, instead of the erse end being dragged along, it rolls, preventing severe damage.