When I'm reading the code I need to understand what it does, the underlying characters are just a medium. I can see way quicker that a complex boolean expression is wrong when I see ≠ instead of != and ⪖ instead of >=.
I do agree with the Butterick that when presenting code to others, for example as examples, the ligatures are a big no, because in this case you actually need to see what characters you need to input.
In that case it works reasonably well, but how do you represent the difference between `=`, `==` and `===` in javascript. IMO =, == and === is much clearer and more visually distinct than ≔, = and ≡.
Mainly a force of habit. But I agree that for equalities a split sign would be clearer for most people.
I won't be going around and trying to convince people to use or not use ligatures though. I feel that it is a very personal preference much like the choice of syntax colouring theme.
I never use == in any circumstance anyway, but telling the difference between the == and === ligatures are really not hard. The === one, at least with JetBrains Mono, is much larger.
I do agree with the Butterick that when presenting code to others, for example as examples, the ligatures are a big no, because in this case you actually need to see what characters you need to input.