Homes on districts that use 127v also have a second phase for 220v, mainly for shower heads, electric ovens, etc. Commercial property always have 220v.
Then they don't heat same volume to same temp, it's thermodynamics
Yes but they are also less efficient because they don't have point-of-use placement
wow, 20-30 amps at the shower head... that sounds a little frightening
point-of-use electrocution
Reasonably safe with ground fault circuit interruption.