anyway why would anyone want to anihalate a wall?

its so fun to siege a settlement, knock down the walls, and storm the streets...and its easy too if you know how to storm a city with little casualties....breach walls at multiple places...then send in a unit to be killed...sometimes, they are able to survive...when the enemy divides its forces, send in troops through the other places...surround the enemy, and slaghter them all! simple...