I really appreciate that the annotations are in the MN-specific database and not directly in the PDFs. It allows me to mark up my documents extensively and then still be able to send completely “clean” copies to other people. For example, when I’m teaching a graduate seminar, I may read and mark-up an article, but still want to send an unmarked copy to my students to read.
Also, my marginalia will occasionally get a little salty! They’re just for me, after all.