Hi Engberg!
Tags are great, but the are bit different:
1. Notebooks/folders are much more familiar for all the desktop computer users, because we all know folders and subfolders well. So multilevel notebooks hierarchy is kind of "essential" notes organazing.
2. If I am within a notebook, creating a new note will assign it to this notebook with no any extra actions. With tags, I shoud not forget to assign tag to the note to find it later.
P.S. BTW, is there an option to find "all notes without any tags" or "all notes without a specific tag"? This is to find such "forgotten notes" from (2)