Why King George VI fits a ballistic-missile submarine

Why name a Dreadnought-class ballistic-missile submarine King George VI?

Because ballistic-missile submarines function as modern capital ships, making a royal name inherited from the battleship tradition appropriate.

The answer starts from the Royal Navy tradition of giving royal names to major capital ships. Ballistic-missile submarines now carry the strategic weight once associated with battleships, which makes them modern capital ships in this interpretation. On that basis, King George VI is a suitable name for a Dreadnought-class deterrent submarine rather than an arbitrary transfer of a battleship name. The naming choice communicates status and continuity as much as it commemorates an individual monarch.