What an informative video. Thanks for sharing.

You can use both but the distribution bars must be loaded to transfer weight to the front axle of the TV and the trailer axles. I have bags on my truck for those special roads that result in the suspension bottoming on the jounce bumpers. With the bags supplementing, weight distribution is still present while the bags provide additional support on unmanageable roads such as I-69 headed south toward Elkhart. To only use bags could result in overloading the rear axle since there would be no weight distribution.
This video makes that point where bags alone should not be considered unless the rear axle can handle the load.