Markdown is worse than other formats in many ways. It has several ambiguities, there are significant variations between implementations, fairly basic features like tables, footnotes, strikethrough, etc. are "extensions" that aren't widely supported.

The only real advantage of markdown is that it is has because more ubiquitous/popular than others, possibly in part because it is relatively easy to implement, as long as you don't care that much about exact compatibility with other implementations.