Increasing the power supply voltage allows the mics to handle louder sound sources. Are you running into the mics overloading at loud performances?
Generally, the way these mics fail is you pass too much current though them. As long as you make use the load Resistor between the supply and the capsule FET large enough, you can’t easily hurt the mics. For 3V it should be about 3000 (3k) ohms, for 5V it should be about 5000 (5k) Ohms, 9V = 9k, etc... If you get a battery box with a higher voltage (more than 3V), it should have the right load resistor since they don’t want to hurt anyone’s mics.