The markdown extension should have a setting: Hide toolbar. One may want to allow markdown if you know it, but not show the toolbar. It can easily be hidden with CSS, but the less custom CSS needed, the better.
To further explain my logic: if you know markdown basics you may not use the toolbar. If you don’t know markdown, tapping on the toolbar could confuse someone who is not very tech savvy. They see the URL code populate for example and fill it in wrong. So, might as well (for some communities) hide the toolbar yet allow Markdown.
