I don't know why but RV manufacturers seem to interchange 'leveling' and 'stabilizing' in media material and brochures but they do. Yes, the scissor jacks mounted on the 4 corners of coach are usually rated to lift 3,000 - 5,000 lbs each. But the frame rails cannot support such lifting methods from the perimeter corners. You will twist/torque/stress the frame. You'll see the effects with interior doors, storage doors, and cabinets. Ask me how I know.
Proper leveling systems will place lifting jacks close to the axles. 4 point leveling systems that have fitments on traditional travel trailers have a set close to the axles, not on the outside corners. Take a look at the picture below at the Ground Control system on a Laredo TT. Larger 5th wheels and toy haulers will use a 6 point system but also have a much stronger frame.
With a manual crank handle, one can easily over tighten (raise) a scissor jack to a point of stressing that corner. What helps eliminate this is an 18 volt cordless drill. There's enough torque in the drill to deploy the stabilizer jacks but with minimal risk of over tightening.