115 Volts or 220 Volts ?

Why the difference between the European and American electrical systems. Is there an advantage or disadvantage with use of either. Just curious what the rational is if any.
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Higher voltage means less current for a given number of watts (power) so you can use smaller wire. That's why automobiles changed from 6 volts to 12 volts. Aircraft, where weight is important, have gone to 24 volts. This is a pain because you can't use jumper cables from your car to start the plane if the battery is dead.

You can kill yourself easily with 115 volts. The trick is to make a good solid connection with the hot wire and ground. If you just brush lightly against the hot wire, so that little current flows, 220 feels about like 115.
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Besides the voltage drop fact, a 240V line is quieter than 120V one. The two hot lines, 120V each, cancel each other noise. I have a dedicated 240 line for my audio room. I own
Linn gear which have a voltage selector switch. My partner is an electrical contractor, he once told me that some countries use 240V because it will cheaper for the consumers. Last time I went to Germany a gallon of premium
unleaded was close to $5.00, that was 4 years ago, imagine the electric bill they mut pay.
Thank you for the responses! I wonder how the difference factors into the construction of power supplies which I understand is crucial for construction of 'High End"' audio?