If only we stopped up energy by making new GPUs and CPUs solving puzzles for random cryptocoin that is not a real currency used for trade and simply a gambling

If only we stopped up energy by making new GPUs and CPUs solving puzzles for random cryptocoin that is not a real currency used for trade and simply a gambling game of speculation. I wonder what would net energy saving be if crypto currency was deemed illegal - as in making it worthless by criminalising the act of converting *coin to any real currency.