I think there is use for good WYSIWYG-Markdown integration. Can't really speak for others but, when writing longer forms of content (technical blog posts, docs, etc.) Markdown becomes a bit more difficult for me to navigate. I always fallback to a visual editor (even if it's just StackEdit) and then try to somehow convert that content back to Markdown destination (which can sometimes be hard).

Vrite's primary format is JSON, but with MD shortcuts, parsing on paste and parsers converting JSON to MD, I think it integrates quite nicely in most cases.