Ditto the most all of what you said. However, as a youngster growing up in a shotgun only state, I fired many a slug through a smooth bar H&R full choke single shot with no damage. After all, the land of the slug is softer than the steel of even the barrel being full choked. All one has to do is look at the rifling on a slug to understand that it's like fletching on an arrow it's the air that makes it spin for accuracy I had never heard of a rifled shotgun barrel until saboted slugs came out.Because not everyone's completely familiar with all shotgun options...
I don't mess with slugs, because I don't know what kind of choke my 870 has, or if a slug would damage it. Plus, I'm happy with .00 buck. But if I were to decide to shoot some slugs, I'd need to look up which kind to get because it's just not a regular concern for me.