Unfortunately, there’s a small amount of relatively common things you might want in literals that can be very confusing in monospace display: tabs, of course, but also all the other spaces (en, em, hair, etc., legitimately needed if you want your typography to be up to 18th-century standards and not argue about the “single vs double space” typewriter-age nonsense), hyphens and dashes and minuses (aka “why I’m still using -- and --- in my TeX code”), and so on.
I use the proper dashes, too, in prose (but when using TeX I use Unicode input these days). But even though some programming languages (such as Julia) would allow one to use the different dashes for different purposes, I don’t think that would be a good idea: they look too similar in, as you say, in monospace fonts.
