You'd lose a lot of energy in the cables in the walls of your house that way. The same reason they use very high voltages to transport the electricity and only

You'd lose a lot of energy in the cables in the walls of your house that way. The same reason they use very high voltages to transport the electricity and only step it down to 240 as close to the end-user as feasible. I won't bore you with the physics, but you want to keep the amps as low as possible (which can be done by keeping the voltage high).