I mean, I don't hate them, but when I was reading this code, I came across a section that had what I presume was "===" (three equals signs) but it was three ver

I mean, I don't hate them, but when I was reading this code, I came across a section that had what I presume was "===" (three equals signs) but it was three vertical lines the length of em-dashes stacked on top of one another, and this looks like absolutely nothing I can type. And, I think that's really my objection to coding-specific ligatures. When you're used to them, you can "instantly realize what they represent," but they're rarely as clear as simply displaying the characters that you type. Historically, ligatures come from slightly tweaking the aesthetics of letter pairs or triplets to be (subjectively) more readable, never in ways that obscure the actual characters. Coding ligatures are arguably designed to obscure the actual characters being typed. That might be relatively inoffensive, like joining the characters in "=>" to make it look like an arrow, but it's not materially helpful -- and sometimes, like the Three Mystery Lines, it's actively puzzling.