The commenter is referring to the editing experience, not the rendered output. Most people edit stuff like typst and (La)TeX in a code editor with a fixed-width

The commenter is referring to the editing experience, not the rendered output. Most people edit stuff like typst and (La)TeX in a code editor with a fixed-width font. Emacs supports variable-width fonts just fine and in theory you could use variable width for the "content" and reserve fixed width for the code. Not sure how well it works in practice, though. Of course, that doesn't go as far as TeXmacs.