David K. Brown says that the battlecruiser's performance in the war proved Admiral Fisher's concept was correct

Actually, the Invincible class battlecruisers proved the concept was successful. Their debut was at the Falklands, when they ran down and sank the German armored cruisers Scharnhorst and Geisenau. Their next action was against the head of the German line at Jutland. Their accurate 12-inch fire heavily damaged the German Lützow, so that the only thing the Germans could do was scuttle the ship. Of course the British had another problem: they were using Cordite as their propellant of choice for their guns. Cordite was nothing but trouble, and should have never been used.

The British should have been warned by the Dogger Bank action, but they did not realize that Cordite was as unstable as it was. Continued use of Cordite probably caused the loss of the Hood. Certainly, inadequate deck armor was a problem, but that alone should not have doomed the Hood. Instead, it was cascading explosions of Cordite that was the real cause of her loss.