So the answer to my original question is - yes :)
If you rewrite your comment with lists I think your question becomes self-explanatory.
<h1>My Title</h1>
<p>This is a paragraph.</p>
For sure, you need an end tag, and Markdown doesn't. But for simple note taking, are you really writing deeply nested HTML?You can comfortably read plaintext that has a little structure, while HTML adds some ceremony that makes it a bit harder to glance at the material as the tags are much more in your face.