The ancient Python maxim is "Code is read a lot more than it is written" and I've always found that to be true. Looking nice is a benefit to readability. Readability is a key part of maintainability (you have to find what you are about to edit first). I find that I'm more likely to catch simple mistakes with ligatures than without, which is also a boon to editing/maintainability. (For example of that, in JS/TS development Fira Code's === ligature isn't just wider, but has an entire third extra line in the vertical stack, making it in my opinion far easier to spot.)