Humans eat duckweed, and in fact it's great in salads (not that I would know personally). Aquaponics is without a doubt very sustainable. I'm not sure about the context of your statement as aquaponics being unequaled. In what respect, and in comparison to what? I can think of equal ways to grow or even better. It also depends on the context. Anyway, food for thought (pun intended). I am glad to see you are so dedicated to aquaponics!