Is it too much to ask LaTeX aficionados to use ASCII symbols where LaTeX isn't supported, or does using "$\mapsto$" instead of "-->" give the writer more academic street cred?
Probably not too much to ask, but more difficult than you'd expect. LaTeX is one of the best, most expressive ways to type mathematical expressions... and once you've spent several years in grad school doing so, it becomes second nature. You actually have to think about ascii-fying it instead of just typing $...$ expressions. :-)
1) I'm often copy/pasting from publications, and the PDF-rendered glyphs don't turn into proper unicode either (OSX, Preview, paste to Firefox, at least)
2) There are conventional differences between the different arrows such as using a arrow with or without a superscript star versus single-bar down versus double-bar down, etc. and trying to render those in ASCII would be quite confusing for the reader and author. Each of them have semantic meanings, and putting in what is usually used as a single-step arrow in a big-step semantics because you lack the glyphs makes an experienced reader's head hurt.
Extensions exist that convert LaTeX to images on-the-fly.
And in a lot of cases (∄ comes to mind) there's just no good ASCIIfication, so inline LaTeX is almost as good as anything else even for people without those extensions.
