except that just about every time I've tried this, I've quickly run into places where trying to use a proportional font creates visual fails. There was a whole 'coding font' family designed around the idea that we should be using proportional fonts for this, and it makes a great case. But it begs the first-principals question- why code using a monospace font? Today, every major editor that isn't terminal-based supports proportional width fonts beautifully.
