This is a deeply personal choice, I feel. I am not a fan of using ligatures in programming code as it gives some abiguity around how many characters are in a given ligature.
To each his/her own, I guess.
To each his/her own, I guess.
Look at the "!=" ligature in the Fira Code example: it's a ≠, but it clearly takes up 2em of width.
Otherwise we wouldn't even be discussing typefaces.
For instance, in the examples from the article, the == and -> ligatures in particular look like something I might not always see as two characters.