I see GVWR's and payload ratings as useless and outdated in regards to most light duty trucks. It is generally just used to know how much to tax you and for EPA emissions/USDOT standards. This forces auto manufacturers to arbitrarily limit these trucks to meet standards rather than the actual safe carrying ability of the axles.
It is only people outside of the medium and heavy duty industry(like "internet experts" in forums) that mainly worry the manufacturers GVWR and payload when it comes to weight enforcement. Most people in the medium and heavy duty industry generally go by GCW, axle limits, and the weight on each individual axle since this is what is enforced in most areas.
GVWR's and payload ratings are good to go by if you are a novice to towing or hauling which is why I recommend those new to RVing to follow them for the first year or so of owning a new rig. Most experienced RVer's and tower's with a few years behind their belt in a vehicle knows what their rig can handle. The more experienced ones can generally look at ALL the specs of a truck and can tell how much a truck can actually handle regardless of what GVWR or payload number is. Of course, there are always those that like to push things way past the safe limit of all of the trucks ratings(even GAWR's) regardless of towing experience.