Lots of people have been killed by people with zero IS.
Isn't that the point?
No one...not one...is saying it's necessary to fight or will teach you to fight. IMO,it is a great aid though, should you choose to do so.
I...am stating that:
a) it is the cornerstone of the Asian arts.
b) It is the source of aiki
c) it IS a better more efficient way to do martial arts
d) it doesn't diminish with age like normal power does
Seems to me that those advocating it are NOT over-selling it. A good way to put it is to quote Some teachers
Bill Gleason "This is what I went to Japan to find."
George Ledyard "I wasted about 25 years training in a way that one day I realized would never result in the skills my own teacher had."
Ikeda has so many You would have to look them up.
Howard told everyone here what he Thought
Two Daito ryu Shihans changed their training on being shown certain ways to train.
It is rather interesting that people with up to 45 years experience in Budo made a dynamic shift upon feeling those who train this way!.
Everyone else can keep lifting, doing cardio and circuit training as far as I'm concerned. I wish them well.
All the best