I did.

You cannot say "Nitrogen doesn't expand" but then say "well some, but less than "norm" compressed air."

Either the discussion is "does nitrogen obey the ideal gas law and expand just like air and all other gases or does it not?"

As a separate issue, we can discuss the impact of MOISTURE in nitrogen and the impact of moisture in air.

Moisture free air = moisture free nitrogen

Uncontrolled air< moisture free nitrogen

Uncontrolled nitrogen at tire store = uncontrolled air at tire store

So why spend $30 for nitrogen at the store? IF as JCL comments, the nitrogen is drier than the air (and there are no specs on this, no claims on this, no data on this) then the DRIER the fill the better, but otherwise no benefit.