Such a sleight of hand, first you mention transformer connections, then you jump to voltage differences.
What "power" do you consider is wasted with:
Delta system at 240V
Wye system at 240Y/138V
Both points I seem to unsuccessfully be trying to convince to Ron from early on.I was thinking 1.17something for the square root of 3 instead of 1.7something. Brain fart.
But the difference between any two low voltage distribution voltages is just a difference in the windings ratio of a transformer supplying the end user. It doesn't mean that anything is being wasted.
So the voltage is 32 volts less, nothing is "wasted" though. Some changes in the advantages and disadvantages have been created but nothing is lost.