Great info. I think the last time I did them was about 5 years ago or more so I pretty much put them on the same level as what you just described.
No. I don't have to try everything to get an understanding of its usefullness. That leap is the same path taken by HIT promoters who claim that you couldn't possibly know whether HIT isn't the greatest thing on earth until you try it for an extended period of time.
There are enough similar approaches that I have tried to understand the mechanics of it. Are you upset because I didn't write that this was the greatest concept on earth? I didn't even insult you.
No one is in the dark about this, and again, I wrote that it isn't something I would do regularly but other trainers may find some benefit from it...just like some benefit can be had from 21's.
Just like that, however, I doubt many trainers would have someone do 21's every biceps training session.