Hey Phenyx. (Good to see you again)

How about this (and I'm just spitballing here..): It's not about "teaching"... it's about having an experience. That is, the sub having an experience and the top giving the sub that experience.

Seems to me that BDSM is about experiencing a wider range of emotions and sensations than so-called "normal" people experience.
And so if orgasm denial turns you into a needy clingy mess then maybe the point is to let you fully experience being a needy clingy mess.

Me? I think I'd like to be reduced to a drooling mass of sexual flesh, high on endorphins, and not about to think straight. I think I'd like that. And if I can get my partner so turned on, and fucked so thoroughly that she can't think straight, that seems good to me too.

Good to see you again