For
It saves surface space and hides utilities.
Against
It is very expensive and risky to construct.
Anonymous excerpts, translated where noted.
“Moving wiring underground where possible is good. My neighbourhood is that, and as far as I'm concerned it's a triple win.”
“Main benefit is no more power outages from storms knocking down lines.”
“Below ground also means whenever they need to do maintenance, they are tearing up the streets, sidewalks, and everyone’s lawns.”
“Burying power lines is 20x the cost”