Of course not; everyting should be in the same damned monospaced font in a text editor for writing code.
The only actual reason I can think of for it is alignment, and that seems like a minimal benefit really. Variable width text is generally considered easier to read, so why couldn't this also apply to code?
It's not just for neatness; either. Alignment shows where differences are between similar lines. And not necessarily consecutive lines. For instance, if we rapidly flip the editing window back and forth between two buffers showing similar code, we can see the differences as the moving parts in a two-frame animation.
Even in proportional fonts, the digits 0 to 9 get the same width. Why? So that tables of figures will look reasonable.
We don't want 1111.11 looking narrower than the 100.00 in the preceding row.
I want everything to be crisply aligned between lines like:
xr = x * cos(theta) - y * sin(theta);
yr = x * sin(theta) + y * cos(theta);
Because alignment.
>The only actual reason I can think of for it is alignment, and that seems like a minimal benefit really.
Most programmers I know would argue otherwise, including me. Wanna try a poll?
>Variable width text is generally considered easier to read, so why couldn't this also apply to code?
Because it's only considered "easier to read" for general text (books, articles, etc) where you don't need to quickly see anything standing out of the ordinary, and alignment doesn't matter.
Even for traditional uses like accounting, "variable width" is not considered easier to read.