To each his own I guess... I find ligatures show intent, are easier to identify and help instantly identify typos (== vs ===). I also find the things that ligatures replace are usually ugly "programming specific" sequences of characters. For instance, arrow functions look much better with their respective ligature because the equals and greater than characters are guaranteed to be aligned perfectly.

I'm primarily working in Javascript, so it may make more sense to use ligatures in my dev environment. And, as others have said, ligatures need to be explicitly enabled in your editor.