Just to add the basic idea, the amount of power is amps * volts. So to carry the same amount of energy with a higher voltage, you can you use less amps. The amount of amps impacts how big the wires are, lower amps need smaller wires and that means less space for wires but more importantly less weight of the wires. There is a lot of wiring in a car. Tesla claims this could be 1/4 the amount of copper wiring in an article, below.

This article describes a bit about this, but also says something I never heard, that there were 6v auto systems in the 1960s. https://www.mining.com/new-tesla-low-voltage-system-a-big-de...