The premise of Tufte's work make sense until you try to apply it to functional and usable user interfaces.
He has strong opinions strongly held but as someone who's designed industrial strength UIs for over 20 years (networking CLIs & UIs, CAD modeling/simulation, Devops dashboards, cybersecurity tooling) I've read all his books, attended his lectures... he's a king with no clothes
Unfortunately, the site was butchered a year or two ago with a redesign to make it look like a garden-variety Wordpress blog. A ton of content disappeared. The front page is reasonably dense, although one might also just call it cluttered, but the subpages are worse - sometimes a single paragraph lost in a sea of wrappers.