Mars, I don't know what the parameters of this workout are (capped, can't watch videos) but I have been periodically doing Ian King workouts for years where you use pretty low weights but a lot of multiple supersets (with slow eccentric etc) and they have been beneficial. Often they have you using pansy weights. Doesn't bother me and there's no doubt that they make you stronger. I don't know about doing ten sets in a row though (or whatever it is), I think that is excessive for naturals.
Personally I have no problem with pulling straining faces curling epic 8kg dumbells.. my body responds well to stuff like this and it all translates to better capacity to handle heavy workouts. Wouldn't do it all the time though.