> I disagree with the premise that you need to be able to actively recall facts like this

Same. The goal is to differentiate things. I code mostly in Clojure and I love functional code, so the one thing that really stands out is anything that does mutable things: for example there's swap! in Clojure and that one is "bold fluo blue on a near dark background". I don't use it often, so it sticks out like a sore thumb. But I don't need to remember which hexcode I used for the fluorescent blue: I just know it's obvious.

Same for "rainbow parentheses": it helps visually see where the matching closing parenthesis is without needing to put the cursor on the opening parenthesis (which I can do too if I want).

My color code is mostly toned down too.