Given this paragraph about autonomous buildings, why would they be safer during a military attack?

Context: Advocates of autonomous building describe advantages that include reduced environmental impacts, increased security, and lower costs of ownership. Some cited advantages satisfy tenets of green building, not independence per se. Off-grid buildings often rely very little on civil services and are therefore safer and more comfortable during civil disaster or military attacks. For example, Off-grid buildings would not lose power or water if public supplies were compromised.

Answer: Autonomous buildings often rely on less civil services and are therefore safer and more comfortable during civil disasters or military attacks.