Reasons (5)

"Hey, Billy… what are you even saying?" Icarus asked while frowning.

"I am just saying that there is a better way to solve this mess," Billy said. "You don't have to rely on total annihilation to quench your anger. Hit where it hurts and get rid of the pieces that are the core of the problem. If you play your hands right, you will only have a bunch of confused people without resources to go after you after this is over."

"... Tell me more," Lucyna said.

"Destroy the dungeons and while they are busy trying to stop you from doing so, aim to their pockets and get all of their money," Billy said. "After getting rid of those, you can exterminate the nobles of this state. Once the population sees what happened to them, they won't try to take their place, they won't even have the means to do the same as the others without the dungeons, so they will be forced to look for other ways to live their lives."