The class can look unnecessary when judged from the war's sudden end and its limited postwar niche. At the time of the decision, Britain still expected an invasion of Japan and wanted more strongly armed anti-aircraft destroyers. Weapon-class ships occupied a useful construction slot between smaller C-class destroyers and the larger Battle class. Their purpose was therefore tied to shipyard capacity as well as tactical need. A late wartime order can be rational even when events soon remove its mission.
Notable Point · 58:16-59:23
Why the Weapon class was not simply a late-war redundancy
The Weapon class made use of yards able to build something larger than a C-class destroyer but not a full Battle-class ship.