Speaking from a D70S user point of view.
When you activate NR for long exposure (> 1 min), there's some in-camera processing taking place which would render you unable to take the next picture until this processing is finished. And the time it takes to process the image is unpredictable (at least to me)... maybe 5 sec.
It's OK if you use for other situations but our Lunar New Year fireworks is over in 2-3 mins max.! IE, you have less time to manipulate.
Also, I find that images taken with NR on (again at least to my eyes) tends to be a little soft. Of course, you can post process but lets just talk about capturing good images straight out of the camera.
By all means, I always believe you should try everything yourself and not just listen. Except that we are talking about fireworks here (short duration). At least we are lucky that we have so many days (this year) to experiment and learn from our mistakes.
Regards