Perhaps aesthetics as a function of quality?
Generally I always felt that chroming was applied to the higher end frames, the more, the better?
Now these frames were generally Reynolds 531, and the component groups were generally higher end as well. So when you rode up on group of riders and noticed the chrome forks and stays on a bike, you could tell which who was riding the < 23lb. bike before you could read the decal to see what brand it was.