The extension is for you if you often write blog posts, documentation, readme files and other things in Markdown.
Since now you do not have to use any external tools to do it. Usually, such tools provide Markdown preview feature, but they are not convenient to work.
No more trade-offs. Now you can work in habitual editor with all necessary features like proofing, collaborative editing, cloud synchronization and get Markdown preview feature without leaving Word.
Formatting tools are coming soon.