Yes, it is all about capacity.
It is much easier to store "volts" than it is to store "amps"
Higher voltage means less current so it becomes more efficient.
Now the interesting thing is the resistance of dry human skin is about 14V .
This is why cars stopped at 12 V.
So 80V is well above the resistance of sskin so you would hope the insulation is working well and don't use them in the wet.
Hold still wasn't that one of the reasons why we started to use cordless in the first place.