Groups vs notebooks

I'm working on a note taking app. One of the feature is that you can group the notes in a folder like manner in which one can create. subgroups inside groups and more subgroups and put notes/notebooks inside it. The app has also a feature where the user can make notebooks in which the user can add notes (You cannot put a notebook inside a notebook). But doesn't that make the notebook same as a group without subgroups? How useful this feature can be? Can having both confuse people? Thank You.