“It’s important in racing because the nitrogen from a tank is dry, and there’s less variability in the temp vs pressure curve. “
Air from a tank is ‘basically’ dry. Consider that the ‘moisture’ in the air is water vapor ... a gas. All gases expand according to the formula PV=nRT. Granted that the coefficient does change slightly for different gases and at different pressures but not so much to be noticed at these conditions.
He must have said that at least half a dozen times in the interview a few minutes ago.