Boy there is sure a lot of misconception on the internet about nitrogen. I really don't see a benefit to using it on the street in tires. Sounds like a gimic for people who here about racers using it so it must be good for them too. On this link http://www.nitrogendirect.com/N2Info.htm
under aircraft/racecars i think is the best answer. aircraft and racecar brakes can easily get to the point where they are red hot, and the last thing you need is oxygen anywhere near that.
As for painting which is how this all got started, the only benefit I can see is the moisture control. The problem is nitrogen generators are cost prohibitive for even big paint shops. Bottles wouldn't last very long. I don't know, it's probably a good ides but so is a full professional downdraft paint booth and not many of us have those in their shops. Buy a couple of good airdryers/moisture filters and worry about more important tools.