I personally like that it allows very simple note-taking for me. I don't need to think about where to store that note, I just write something down. When I tag/link it, I'm almost guaranteed to find it again.
I have templates for e.g. meeting notes or my daily todos, which are helpful because they make it easier for me to find notes of a meeting with a specific person (because each person is a link as well).
It also offers whiteboards and a fancy graph view, although I don't use either much.