As a Veteran of Vietnam, I can tell you from first hand experience that war is useless and a waste of good lives. Someday, good diplomacy will replace the need for it.
Is war important?
Of course. War makes people live a hard life.
We can say it's important, but eventually it's bad to make a war, as each war had killed a lot of people and ruined many houses and places, anyway making war is harmful for all.