I've been telling them Cape guys for 15 years now to use a full sink line in shallow waters. That's what I have been using in Barnstable or Brewster flats.
We fish from a boat so the sinking line stays at the bottom forcing the fish to keep his eyes looking forward not up. We disguise our location better since we are at the surface floating.
Secondly, since the Cape flats are mostly sand, the line and fly dragged over helps promote a sand eel explosion my moving particles. Gets them rev'ed up!