Why all-forward guns suit a battlecruiser better than a battleship

When is concentrating a capital ship’s main armament forward a good design choice?

It can be efficient for a fast battlecruiser with room to manoeuvre, but a battleship in confined waters benefits more from an aft firing arc.

Concentrating a battlecruiser’s main guns and magazines forward can shorten the armoured citadel and free the stern for machinery. A buffer between the magazines and engine spaces helps keep heat away from propellant while improving the density of the machinery and protection layout. The arrangement works because a fast battlecruiser in open water can manoeuvre to keep its forward arcs on the enemy. A slower battleship fighting in confined waters such as the Baltic, Adriatic, or Black Sea may not be able to turn in time, making an aft turret much more valuable.