What I see as disadvantages are: It is not possible to render it properly or have support for it beyond showing plain text. Many users might write things different from each other, which might affect how easily a reader picks up what each document's style or conventions are.
Sure you can, and indeed that's what markdown was originally supposed to do (at least as it was first described to me). The catch is that you have to treat the plain text as the authoritative version: you do not edit the plain text in order to produce changes in the rendered document; you edit the plain text for it's own sake, without considering the effect on the rendered version, and the rendered version is derived from that.
Missed this and too late to edit.
0: Which historically meant "not stupid-quotes", with a addendum for stupid-dashes, stupid-ellipses, etc, but now also includes "not emoji".
The most annoying thing about Markdown is that most of the time (90%, I'd say) it's added some kind of formatting, I was not trying to format anything at all.
Can't speak for anyone else, but for my part there is animosity towards any format, period. Documentation should be plain ASCII - or, when strictly necessary[0], UTF-8 - text, and readable as such with only human-generated ad hod syntax such as *emphasis* or
or http://links.to/whereever.written-literally. To the extent that markdown is tolerable, it's because it does not demand any obfuscation in how documentation is written.Admittedly, I'm not necessarily a repesentative example of anything.