This could be interesting to control the flight of AWE wings, for example for an easier and faster reel-in depower phase.
Reflex bridles were added to hang gliders in the late 1970’s / early 1980’s to prevent unescapable dives that occasionally drove gliders straight into the ground. With no schools for hang gliding yet, and limited information available, I used to have fun diving my “standard Rogallo” glider in 1975, never knowing of the danger. Lucky for me, I never got caught in a dive I couldn’t pull out of. 
Interesting video of parakite, doing up and down motion which made me think about yoyo reel in reel out https://www.instagram.com/reels/DXKUl1LjCkB/
It looks like soaring at the top of a dune, taking advantage of the updrafts on the windward side, then the downdrafts on the leeward side.