Markdown can be extremely helpful and result in increased productivity for those familiar with and used to it. Unfortunately, if you are a Markdown expert and think you can use the full breadth of the popular syntax in Docs, you will be sorely disappointed. For example, Google Docs does not support inserting images, block quotes, horizontal rules, or many other things that can be usually done in a full Markdown text editor.
I would have also liked backticks for using a fixed-width font. That’s very awkward to do any other way in Google Docs.
In any case, this is a welcome improvement