cause it was like that on the 360
in Europe we get current at 220 Volts and 50 Hz for alternative current while in the US you are at 110 Volts 60 Hz
while numerous device (computers and small appliances) do have a PSU that can accept power from 110V to 240V and 47 to 53 Hz and therefore be plug worldwide as long as you have a plug adaptor some of the bigger one do not always come with one like the 360 for instance or a lot of the bigger device (my TV and Amplifier are both 110 60hz only) and I have two choices here either to replace the PSU or to run my 3000 watt power converter...
Hz don't really matter usually since it is not a mechanical engine and the PSU converts it in direct current anyway








