In my experience, all of those features really slowed down my reading: the superscripts, the underlines on all the links, the serifs, and the visually heavy popups that appear immediately after hovering; contrast with Wikipedia's popups, which feel much lighter.

Thankfully, the site has a built-in reader mode to make most of this go away, but it also removes the good features, like sidenotes, and I have to wonder: if the reader mode is for reading, what's the "regular" mode for?

Also, typo: "epxnesive".