I didn't watch the video, spraying paint is not something I do I leave that stuff to the experts.
I felt I must comment on something you said
The fact is compressed air is dryer than the ambient air that is being fed into the compressor.
The filters or "separators" aren't perfect. The problem is compressed air has SOOOO much moisture in it. The filter has a LOT of work to get it out. First the air needs to be cooled, then ran thru the filter.
Anyone who has used a compressor should know this because the last thing he/she should do after shutting the compressor down is drain the water out of it and the filters/traps in the lines. This should tell you there is LESS water coming out of the compressor than going into it. Compressing air lowers it's dew point making it unable to hold the same amount of moisture.
The reason it is a problem in compressed air machinery is because
it can't exist in the compressed air in as much of a quantity as the ambient air and therefore gets displaced as condensation in the tank, lines and tools and will get occasionally displaced and blown out with the compressed air thus ruining your paint job.
Having said that it does not remove ALL the moisture and I can certainly understand there is more reason to use Nitrogen on painting and other processes that are H2O intolerant but having done a bit more research on the tire issue I am convinced that it is another marketing scam to make us pay for something which we presently get for free!!.