From my experience with it I can tell you that it is most certainly benificial. There is a road in my town that has a hair pin turn in it after a bridge that I use to guage suspension perfomance.
Before the bar I would have to cut in before the Apex of the curve to exit well. This is because without the back following through curve at the same angle as the front it would load the front end causing the tires to slide out. In effect pushing the front of the car across the road. I will over compensate for this which would cause the me to be unprepared for when the tires would catch and put me into a barrier if I don't quickly recover.
After the bar I am able to cut the wheel alot later and swing the back of the car around in the turn, giving me a greater exit speed because the back is more loaded and doesn't flex under pressure as it would before. This gives it the ability to slide much the same way one would when you lift the Emergency brake.
The Strut tower brace uses lateral pressure and metal fatique over time to press the car back into shape, keeping tension on the bar at all times not just when in a turn.
Does that make any sense?
