However, there is this too from Shioda sensei's Dynamic Aikido:
"Nikajo is a technique directed at the elbow and the wrist and can be used to inflict much pain if applied skillfully' p.74
and can be used to inflict much pain
Certainly doesn't say always. Sure, you can inflict pain - but that's not very interesting to me technically. Any store front Tae Kwon Do school can do the same.
Anyway, my experience with the Yoshinkan in Japan (which also isn't from a video or a book) matches the OP's in that respect.