Markdown is a text markup language, of course. The output does not look like the input (unless you want to read raw text Markdown, in which case LibreOffice works fine).
How would that look in a single-pane, edit-in-place, wysiwyg editor? Where would you type the input, and where and when would it show the output?
How would that look in a single-pane, edit-in-place, wysiwyg editor? Where would you type the input, and where and when would it show the output?