I don't disagree but the FA does say: "In Australia, where gardeners have grappled with droughts for a decade, aquaponics is particularly appealing because it requires 80 to 90 percent less water than traditional growing methods."
I suppose this system really amounts to scrap food recycling. You're feeding the fish various waste organic material that was already grown on a real farm.
The real question is probably: why not just feed it to pigs or goats, the traditional solution? Older folks tell me it was common for there to be residential garbage pickup, separate from trash. The garbage would be taken to farms.
The fish are hungry, that's why not. Aquaponics takes care of the fish waste and plant food, but there is still the question of fish food. Nom nom.