More than you ever wanted to know about
nitrogen in tires.
The quick answer: don't waste your money.
BTW race cars use it for pressure stability, as in "take a half pound out of the right rear" If you can feel a half pound difference in your car or RV then you might need nitrogen.
Aircraft use it due to extreme temp and altitude changes and combustion concerns on landing. If your car or RV can fly you might need nitrogen.