What's the advantage of the frame design on our new TT?

It's cheaper and easier to weld the subframe under the main frame than it is to build a flat frame. I don't get the argument for height as you can easily build a tall flat frame. The bottom of my last TT was almost 20 inches off the ground. On a dodge ram I had to use the equalizer "Drop" to raise the ball two holes on a 2011 Ram CTD 4X4 to get it to ride level. I could barely lower the tailgate without hitting the top of the hitch.