Just because a certain approach works for you does not necessarily mean it works for others. You state that the notebook approach will inevitably fail when lots of data. Well the same will happen with tags only because you end up creating so many tags that you will have to search a long time for the right tag if you need to find a note.
The best approach is probably a combination of both notebooks and tags, both of whch should be sensibly allocated. Notebooks are like Windows Explorer giving a vertical inventory, whereas tags give a horizontal inventory. But, at the end of the day, there is no right or wrong !!