Our car tires have all nitrogen in them, because we bought the tires at TireDiscounters and they include it for no extra charge. I think the main benefits for street use are that the tires lose pressure slower than with regular air, and the electronic tire pressure sensors inside the tires corrode slower if you plan to keep the car for 20 years.
My motorcycle tires have regular air and the little ceramic balancing beads inside of them. I think the tires lose air slower than with outside balancing weights, because there is ceramic dust generated from the rolling beads that fills tiny air leaks.
“It is difficult to get a man to understand something, when his salary depends on his not understanding it.”
― by Upton Sinclair, who helped clean up the meat packing industry and other factories