1. Better organization. One note organizes my files into notebooks and pages. This is really important to me to prepare study notes, as I find arranging the notes just like the technical books' table of content I'm reading.
2. To easily apply Cornell(two columns of hint and description) note taking method.
3. To search easily. Once I studied a book and took my notes well, there is no better way to search and recall.
4. Sketch with my notes. This helps me represent ideas I study into my own mental model. Also great for representing my startup ideas.
5. Record myself into the note reciting the material.voice memo.
6. Doing all of the above on my computer and phone and finding everything in place.
Again, there might be work around for doing all this. But once you get into Evernote and OneNote you find it really hard to go back into text files.