I was illustrating how most of them aren't clutter. They do different things. This list just goes further to show that point - all the text related units refer

I was illustrating how most of them aren't clutter. They do different things. This list just goes further to show that point - all the text related units refer to different aspects of the text, and they all need root and local versions. Same for screen space units like vw, vh, and so on. Any unit where you can't derive one from another means you need both. There are some where you can do that. Absolute lengths like mm, cm, inch etc could just be one unit. Same for deg, rad and turn. Mostly though, CSS units are very well thought out, and it's easy to understand why the length units are included (USA vs metric).