I would assume that book is BS through and through.
Cinnabar is toxic.
Not something to use EVER.
The method of red/cinnabar palm is/was a skill.
Its not practiced much any more due to the toxic material used.
The idea is to train the palm in such a way that it develops the strength and penetrating essence while also being able to seal out the toxins from being absorbed into the skin.
Fanzi quan was famous for its red sand/cinnabar palm skill.
Just because the skill isn’t practiced today doesn’t make it BS:rolleyes:
Counter Point: If something had great worth to the masses it would survive through today in most cases. Somewhere along the line people started to figure out that playing with toxins was stupid and not good for you in general. No magic potion, herb or anything else is going to significantly change your fighting ability.
Cheers
Jake 
I would see it more as be an out moded.
Just as martial arts was primarily a weapons based method with hand to hand combat relegated to what if I lost my weapon.
Same thing is followed today. Military training is on usage of ones armaments (guns) and the physical hand to hand combat as a physical and mental tool at best.
the purpose of training in such esoteric and secretive methods are unnecessary anymore. We are no longer existing in such an environment that made those methods viable.
“Don’t bring a Knife to a Gun Fight”