The drawback on tag structuring in flat collections is that you only see the immanent structure by searching and not by showing.
If you want to share structured information, like projects/circumstances where the structure of presentation is part of the information itself
a) it forces you to put all information/notes into a single notebook, because there are no overall tags once shared
the structure within has to be outlined by a "keynote" or people won't know the structure inferred otherwise by obvious organisation
This means that Evernote generally is more applicable for sharing collections than constructions.
P.S. The concept of "inheriting" context by nesting entities of understanding is quite a real world model and natural, not so much just "old" thinking habit.