If use properly I beg to differ. One of the things I often see in class are some students kinda just going through the motions, they don't do things with true "intent" (for lack of a better term.) I would think adding an element of danger would produce the requisite intent.
It's kinda like going to a shoot house as a cop. When you do room clearing knowing the OPFOR has a gun loaded with simunitions, you are definitely clearing those rooms with the requisite intent because those things hurt lol.
That is mostly a training mindset thing. I don't find them terribly useful because I honor the weapon treating it as a sharp. If I have a student who isn't treating the sharkee that we normally train with as a knife I will up the ante to a sharper and heavier aluminum blade. I have never had a student go through the motion as the aluminum got nastier and the power being fed got harder. To me it is just a budget thing, I can replicate intent with a decent training partner, I don't need electricity. I think it is a nice tool but not hundreds of dollars nice.