Having more current running through a wire means thicker wires. Higher voltage means less current to achieve the same power, so thinner wires for the same power. The tradeoff for higher voltage is it's more dangerous (higher chance of arcing etc).
Agreed. Lately I'm coming across self-hosted services that not only require docker, they essentially require a docker-compose file full of many other dependencies.
The other thing that blows my mind is how many of these self-hosted applications require mysql/postgres instead of just using sqlite.