It is true that NASCAR, and some other top forms of racing use nitrogen in tires and for jacks, impact wrenches, ect.
The reasoning is that nitrogen pressures can be run higher than standard air compressors can put out,
The higher pressures of the nitrogen bottle are reduced by a regulator, where an air bottle usually starts out at a set pressure then lessens,
Nitrogen is completely dry, so guns and jacks work more consistently, giving closer torque tolerances,
And nitrogen doesn't expand & contract in the tires with heat like 'air' does.
There are also contaminants in 'air' you won't find in bottled nitrogen.
Keep in mind that it takes much more nitrogen to do the same job as 'air', simply because nitrogen isn't as dense as common 'air'.
Your source also forgot to mention that the average impact gun set up for nitrogen is about $1,900, and nitrogen is much harder on the internal components of the impact gun simply because you can't lubricate (contaminate) the inside of a nitrogen air gun.
The average floor jack set up for nitrogen is just under $5,000.
Nitrogen is more stable as a tire (pressure) filler.
CO2 is same, just as clean, but much cheaper.
Personally, I'm running an on board compressor, so I'm sticking with air.
The CO2 tank guys usually can keep up, right up until they the tank runs dry...