I have a way to at least make my students puzzle over that problem.
What is cheaper to run, a 4kw heater connected to 120V, or a 4kw heater connected to 240V?
The answer is their both the same. First for that answer, the PoCo measures in watts, so 4kw is 4kw, no matter the voltage.
But the same answer applies to your motor Xhp is Xhp no matter the voltage, it ain't gonna run cooler, or cheaper for that matter. It doesn't pump faster or harder, it's the same, you just save a little (usually negligible) on the intitial installation costs but that's about it.