I'll agree markdown has some strengths and weaknesses. The image syntax is terrible, and even the link syntax is a little iffy. But the bullets and the bolding? Yes, it's excellent, it does exactly what it needs to be. Whenever I need a user to give me rich text for something, I tell them about Markdown. No worries about all the font and styling screw-ups from a word document where the user has pasted text.

"I need the user to give me plain text but they also need bold, hyperlinks, and bullets" is the use-case for markdown. It does this fine. It could do things better, but it does its job fine.

I have had users get annoyed, however, that _underscore_ doesn't underline.