Earlier quoted context omitted.
Many programmers are still committed to manual formatting, or fixed width fonts would have been obsolete already.
Fixed width fonts let you quickly parse syntax. Syntax and semantics are equally important when reading code, whereas semantics are generally the only thing you need for understanding the written language. That said, I haven't seriously tried programming using variable width fonts; maybe it's a well-kept secret to digesting code. Or maybe it's like Hemp Milk, there's a reason it hasn't caught on.
PS: The idea is not mine but I can't remember where I read the instructions about this editor setup, so Google is your friend.
https://gist.githubusercontent.com/diegoperini/853d54c8873e7...