Well, if you want to share your note with someone else, it is easier to share aPDF than a markdown file. I don’t know about your notes, but mine often contain links to both internal and external sources.
The internal ones are meaningless in a shared file, but the external ones are not. The other person can then click on those in case he/she is interested.
In a PDF that was created with a print command, the external links don’t work.