Why an Agincourt battlecruiser conversion lacks a purpose

Why would Britain convert Agincourt into a battlecruiser by replacing her fourteen 12-inch guns and rebuilding the interior?

No convincing reason is offered: the work would be expensive, and Agincourt lacks the prestige value that might otherwise motivate it.

Converting Agincourt into a battlecruiser would involve gutting the ship to install larger barbettes while retaining much of its existing protection. The objection is the absence of a useful reason to undertake that expense. A conversion on this scale needs a value that justifies the work and disruption. Prestige is suggested as a possible motive, but a single Agincourt would not carry enough prestige for Britain to make that convincing.