In short; it doesn't suit our roads and climate. You need a certain amount of water here; at minimum, two large buckets; otherwise you are going to do damage to your paintwork.
I would be OK perhaps in a dry climate where it's only light dust that settles on the car, and at that you'd wanna be washing regularly.

Is it the water rates that has you thinking ahead? For the cost of the bottle of product, you'd have paif for 2000l of water.