Sure, but that doesn't address my question about whether I should use troff versus markdown for things where I don't need the power and complexity of LaTeX.
In my opinion, I'd say pull out troff if you're thinking about making a PDF, or if you want tables or equations (see http://www.troff.org/prog.html). Personally, I mostly use markdown when I want to generate some HTML but don't feel like typing tags by hand, or just as a sort of "style guideline" when writing text files.
I meant when in two years you add something to your tex file and make blows-up, that's a reason to use roff if you can get away with it.
Gotcha, thanks for the clarification. I guess I don't use very many "exotic" packages, so I haven't had much of an issue with old LaTeX files not compiling. Though, I also rarely have to go back and recompile them.