[Isamu]

Most of the need for monospace in coding is for the sake of indentation and alignment. If you have any ASCII diagrams (see the Internet RFC's) you need monospace.

But we forget how much of this is a circumstance of history. Teletypes were monospace, like typewriters, for mechanical simplicity. Line printers and DecWriters were monospace for the same reason. Then the first video terminals and eventually the original IBM PC were all monospace, all for the same reason, and because of familiarity. We simply got used to monospace and came to depend on it. There is no inherent virtue of monospace.

Come to think of it, the first (mainstream) computer I remember with proportional fonts was the original Mac in 1984.