You don't need to drill down through the menu items to get to what you're after, you just trigger 'show menu items' then begin typing in what your after.
So in your example say I wanted Edit ☞ Substitutions ☞ Smart Links, I'd hit my trigger for 'current application ☞ show menu items', then, rather than beginning to type 'Substitutions' I'd start typing 'Smart' & Smart Links will appear as well as Smart Quotes etc.