One reason to put Nitrogen in the light aircraft tyres as well, (I would always do so, if at all available) is the lack of moisture, compared to the compressed air.
Only if it is filtered and stored correctly. Just the same for compressed air. I fill my aircraft tyres from a SCUBA cylinder and I can assure you that the air is just as dry and filtered as it comes from my compressor which is quadruple filtered and used for mixing breathing gas.
Nitrogen has limited benefits in our spam can world, don't believe the hype otherwise.