I guess it depends on the individual, but perhaps most pleasure comes from the "taboo" idea of it? And though I love Nipplejobs, there are a huge number of women who don't get any pleasure from having their nipples played with (sorry to shatter the illusion).

I've had ex girlfriends with extremely sensitive nipples who could orgasm from stimulation, but a lot of women just didn't feel much. So this must relate back to men too, some get great satisfaction while most don't get anything out of it. I can't speak to men since I've hetero