When administrating a firewall different users or nodes behind the firewall may need different filtering rules.
If the exception for an ip applies to all rules then you cannot block node 1 for YouTube but allow Netflix and block node 2 from Netflix and allow YouTube.
The documentation does not matching local exception because they are not exposed by the UI.
Currently the UI is very limited: while the engine works very well, we do not know how many users are considering using the DPI feature.
Still, I thins the actual UI is really too limited and does not express the potential of the backend.