Ligatures in Programming Fonts: Hell No
Ligatures are special characters in a font that combine two (or more) troublesome characters into one. If you have an fi ligature in your font, you identify it with its designated Unicode code point, which is . So in a source file that uses Unicode characters, how would you know if you’re looking at a => ligature that’s shaped like ⇒ vs. Unicode character , which also looks like ⇒?
Source: practicaltypography.com