'Plastic', and then 'vinyl' again?(In the OSM wiki 'Key:building:material' entry)

What is the rationale for the ‘Key:building:material’ key entry in the OSM wiki having a key value of ‘plastic’ and then again having a key value of ‘vinyl’?
As you may know, there are many vinyl-based building materials in use today.
And vinyl-based compounds are often referred to as ‘plastics’.
So maybe I should just call them ‘vinyl’ or ‘plastic’ as one.
But the ‘Key:building:material’ key entry in the OSM wiki has a ‘plastic’ key value, and oddly enough, only ‘plastic vinyl strips’ is organized under the ‘vinyl’ key value.
What is the reason or rationale for this split, or for writing one more when there is already one?
Do we really need to break it up like this?

Plastic is a generic term for all kinds of plastic materials whereas vinyl is a specific plastic material. In other words: Vinyl is definitely a plastic material, but plastic is in many cases not vinyl.

I am sure there are different opionions about the question if it makes sense to use different tags for different types of plastic material or just tag all of them as “plastic” but there are lots of keys in OSM with 2 or more values which are very similar to each other. I would not worry about that, just use the value you are comfortable with.

By the way: “Vinyl” does not only represent “plastic vinyl strips” (which is a poor description anyhow) as documented in the wiki, there are also plates and tiles of vinyl used as decorative facade elements. Considering that I’d say a separate value “vinyl” does make sense as it is a widespread used material.

It’s not the only example in OSM - we have surface=ground as well as more detailed “types of ground”.

The wiki page explicitly says you can use any values you like, and links to taginfo to show what other values people have used.