> only a small subset of html's features.

On the contrary - Markdown is essentially a superset of HTML, so unless you're using a renderer that strips it from the input, you can have the best of both worlds.

This property was super useful for a lightweight CMS I threw together a few years and which is still used by the original customer today. 99% of what they need to render is easily authored in Markdown, and this further helps ensure a commonality of style and device portability.