In some places they are powered. It’s generally much more expensive to do safely so it’s only done in historic places where overhead wires would ruin the place.
I know It’s the case in the centre of Reims for example.
It’s about how some video games do this thing where the lore is barely explained in cryptic sentences by the few characters, and basically you need an online wiki to understand anything about the story of the game.
The games most gilty of this are the fark souls franchise. Good games, but I hate this kind of lore.