With corrosive ammo the practical difference can be significant. Yugo AKs are a prime example as their rifles were often surplussed in fantastic condition aside from a rusted out barrel.
The salts combined with humidity, rain and a difficult maintenance schedule can easily reduce the effective lifespan by half or more. You must be very vigilant with cleaning and maintenance on a non chrome lined barrel to keep it in proper condition, even a hunting trip with no corrosive fired has resulted in rust developing in the bore from high humidity.