You're moving the goalposts.
Your first comment:
> and does not have builtin functionality to export notes (e.g. a menu option to do so)
That's incorrect: you can export to PDF. Certainly not as handy as Markdown, but it's there.
Additionally, Apple offers AppleScript as a way to do even more.
No, this isn't an open source piece of software. If that's your sole criteria for "good" then you're right, it's bad.