The machines that send a hose to each valve purge o2 and fill n2 at least 4 times to get the o2 below 1%
The big advantage for cars is late models w/(federally madated)tpms. less corrosion = longer lasting sensors.
The trucking industry loves n2, allegedly you can air up in sunny Fla and run straight to Canada (why would you want to)
and have less than 1/2 psi difference. More about tire wear life and safety than anything else.
Thats what my NAPA tool rep says.
He also says that in the, not too distant, future federal regulations will probably madate n2 to protect the already madated TPMS, so the time to push sales of the equipment is now while the garages can still charge for this service and make their investment back. Because when it goes madated you wont be able to charge for the n2 svc.
Sounds like an even bigger scam to me. I'd bet there are lobbyists pushing this legislation,to help the manufacturers.