Talk:Medal/@comment-35647060-20180806164809/@comment-9676492-20180806172017

Not mandatory, no. You get a 41cm Triple Turret from upgrading each of the Fusou sisters and they become solid BBV fighters (as opposed to being much weaker firepower-wise before K2), but they're hardly indispensable if you have Nagato/Mutsu for slow BB firepower or the Kongo sisters at K2 for fast firepower.