[erikbye]

Your presumption is that you only ever view them as plaintext. I author using plaintext, but one reason I use Markdown is that it is easy to make uniform looking notes. When I later view, especially longer ones, I do so rendered.

Even if you only did view them as plaintext, it sure is a handy format for a static blog generator in case you'd like to turn some of your notes into a blog post one day.