The contention is that the usage of groundwater removes it from the ground, which has long lasting effects. Long term overuse of groundwater has caused some serious problems. It's of little use to us in the sky anyhow.

Ah yeah, don’t pump your ground water for agriculture, doesn’t matter if you’re dumping it on almonds or grass. I’m well aligned on that.

But water is not a scarce resource and putting it on plants is not a negative sum game.

The planet recycles water. Grass is 100% sustainable if maintained using the planets natural water cycles.

The water in the sky falls on a water shed which is harvested into a local water supply which comes right back to a tap.