I’ve got one and I don’t really overthink the water usage part. It definitely feels like less water is flying everywhere compared to my old nozzle, but I never actually measured it. Works fine for spraying off my patio though.
I used to worry about this too but honestly, for just turning off one lamp from the couch, the app works fine for me. I have a few bulbs around the house and never bothered with a hub, haven’t really run into any issues so far. Having the phone handy is usually enough for what I need.