I think what he was implying was if you were playing C in all its diatonic form, was play it all over the neck and not just on the C ionian shape at the 8th fret. Starting at the 1st fret you'll get an F lydian with C as its perfect 5th. Skip to A relative minor/aelion on the 5th fret and go back down a whole step 3rd fret to G with C as its subdominant key and jump to a diminished sounding locrian on the 7th fret. Playing it that way does in a way help visually show you where everyshape pattern falls in relation to that particular key. You know what they say bout learning scales is to learn them in all its form so its a good thing.