Hi Slinger,
This depends a lot on your model and settings. Some time it would take less render time than a good FG solution and some time it would be the same or slightly longer. You have to experiment with this. Also the settings in the tutorial are just the basic start, you can develop it more to fit your scene and make adjustment for the best time/quality render.
Just remember that this work flow propose is to generate a lighting system that will work well with dynamic scene and not much for shorter render time. So you might get the same render times but along with that the freedom to move objects as much as you want and not being bound to a FG map that has to be recalculated with every move of object, change of material or lights.
BTW, that is where you save so much time. Since you are not fiddling with FG, the scene overall work is much shorter, and the quality is fairly good.
Dani