If a hurricane is aborted at the embryo stage, then all that potential energy in the water, which fuels the hurricane, is never consumed and dissipated by the hurricane.
I think if we tried this, we'd find the oceans to heat up at an even more extreme rate, and create spontaneous weather events that we are unable to prepare and defend against.
In the demo video, they show that you simply check boxes on which apps you want to be available or not in the dumb mode, I imagine selecting signal, and deselecting the default SMS messager is possible