Markdown is primarily for writerly writers with workflows. That's where all the benefits accrue.

That's where it matters whether mark-up is done inline with content creation, or whether it's a post-pass process of fiddly buttons and menu options. That's where it matters whether the mark-up is lightweight, or overbearing. That's where it matters whether formatting is treated consistently from one piece of software to the next, or a constant surprise. That's where it matters whether the resulting file is locked away in a proprietary binary format, or not. Etcetera.

If you're building a proprietary end-to-end service -- for editing a little bit of text, storing that text, and then displaying that text -- whether your solution incorporates markdown is, at best, probably irrelevant.