Is it okay to apply "menubar" role, ... etc and related keyboard shortcuts to the main navigation?

Usually <ul> and <li> elements in a WYSIWYG editor (role="application")
will be given ARIA roles "menubar", "menuitem", and "menu", and attributes
such as aria-haspopup="true". The application will also be applied some
keyboard shortcuts. Here is an demonstration:
http://oaa-accessibility.org/example/25/

Although these ARIA roles, attributes, and keyboard shortcuts are usually
applied to applications such as a WYSIWYG editor, they might be equally
useful when being applied to the main navigation (which has popup sub
menus) of a website.

However, I'm not sure if applying the above mentioned roles, attributes,
and keyboard shortcuts to the main navigation (role="navigation") will
cause confusions or problems to assistive technologies or not. And so far I
haven't seen any website do this to its main navigation.

Will it be a benefit or a problem when doing this to the main navigation?


Regards,
Ian