wrote

As a sidebar, I have gone to many client's houses that have steel
doors installed, and they thought the priming was the protective
finish! Surprisingly, it does quite well, and a good cleaning and you
can start finishing if there is no rust. I have finished doors that
have probably been installed for 2 - 3 years with no adverse effects
to the top coat of paint.


One possible explanation for that is a universal lack of color sensibility.

In my house the missus is the color expert. I am the color idiot/savage,
according to the resident color expert.

Soooo......, to a lot of folks, a primer coast may look like a finish
color/coat. But even I think I can tell a primer coat from a finish one.