In case you're unaware, that's literally why they took to calling it that.
Technically correct, easiest to market back when people were first starting to have doubts about setting stuff we found underground on fire.
Using the word "natural" was very much a deliberate choice.

Not really.
There's plenty of overlap, but there isn't really anything I buy on every hero every time.
There's nothing I'd include in every build, and counter-items aren't needed every match.