100v,115v versus 230v

That is just rubbish unless you have an amp which consumes more than about 1500 watts. Then the standard 120 volt wiring may not be adequate to carry the current. Other than that there is no basis for the claim. 

The whole world should standardize on 300 volts RMS at 100 cycles.  Running at higher frequencies increases transformer efficiency.  Everything would interoperate.  Just do not stick your fingers into the outlet :-)