Some concepts are really important and deserve good attention explaining them.
Others do not.
If I added several pages to this page explaining what “not” and “important” is then it would make this page harder to read.
It’s common mistake in a lot of documentation though to spend a lot of energy explaining obvious things. This makes the documentation worse though because the documentation becomes long and boring and people won’t want to read it.
It’s a problem to make documentation which puts too much emphasis on unimportant things - think of them as edge cases.