Ligatures help to convey the intended meaning of the code, which outweighs the rare case when they go wrong.
Programming languages' operators like == are actually ASCII arts for the convenience of the machines, never the humans. It is encoding a concept that is not representable in ASCII, so it has to be encoded by a conventional combination of two characters. When reading your own or others code, you have to do this subtle mental labor of decoding the ASCII art back to the concept.
Programming ligatures, on the other hand, alleviate this burden. They conform the intended meaning of the author. It's not a typographical problem, rather it's a communication problem.
For most ligatures, you can guess the underlying ASCII codes, and if you can't guess, you only need to learn once. In an editor or on a webpage, you can copy the code and paste onto something that doesn't have the ligature font enabled to learn its components.
The idea case is Unicode programming like Agda, but it has its own problems like not easy to type and find out how to type, lacking some operators, hard to read with small font size, etc.
Ligatures are a balanced option between the ASCII art and the Unicode programming. Not hell yes, but neither hell no.
Programming languages' operators like == are actually ASCII arts for the convenience of the machines, never the humans. It is encoding a concept that is not representable in ASCII, so it has to be encoded by a conventional combination of two characters. When reading your own or others code, you have to do this subtle mental labor of decoding the ASCII art back to the concept.
Programming ligatures, on the other hand, alleviate this burden. They conform the intended meaning of the author. It's not a typographical problem, rather it's a communication problem.
For most ligatures, you can guess the underlying ASCII codes, and if you can't guess, you only need to learn once. In an editor or on a webpage, you can copy the code and paste onto something that doesn't have the ligature font enabled to learn its components.
The idea case is Unicode programming like Agda, but it has its own problems like not easy to type and find out how to type, lacking some operators, hard to read with small font size, etc.
Ligatures are a balanced option between the ASCII art and the Unicode programming. Not hell yes, but neither hell no.