To me,4x4 on a light weight ST will help more with handling than traction...When mashing the throttle,most of the weight shifts to the back and leaves almost no weight in the front(depending on the torque of the engine).Weight will go more places than 4x4 alone will,IMO...Ground clearance is another key to go to those hard to reach places...(Savage)
4x4 does help with traction,but not as much as weight does.