When mixed secondary batteries made sense

Were mixed secondary batteries ever a sensible capital-ship design choice?

They could be accommodated on very large ships, but a unified dual-purpose battery generally offered a more efficient concentration of firepower.

German warships retained separate medium-caliber surface and anti-aircraft batteries, illustrating the older mixed-secondary approach. Exceptionally large ships such as Hood or the Yamato class had enough space to carry both roles without an immediate layout crisis. Even on those hulls, however, designers had to ask what the extra caliber actually gained. A single dual-purpose battery could sacrifice some performance in each role while providing more guns, simpler ammunition supply, and greater overall flexibility.