Jackie Fisher's original idea for the battle cruisers was that they weren't supposed to fight battleships. They were for use as sea-lane protection, because they were almost as fast as cruisers, and could blast them out of the water. I think the problem was they were very expensive and very shiny - so got collected into the main fleet. Plus they had these big guns, and could therefore sink battleships (if they could survive long enough), so if you got into counting guns, and weight of shell, you suddenly started getting delusions of adding them to the battle line.
Obviously they were useful for scouting ahead of the fleet, because they could beat up the enemy's screening force and then run away from the battleships. The problem was failing to run away at the right time.
At Jutland the British battlecruisers also suffered more losses than the Germans. Partly this is because the Germans chose to have more armour on theirs, because they didn't have a huge empire and so carried less fuel and could burn more. But another suggestion is that the Royal Navy spent a lot more timei on training for speed of gunnery than they did on saftety, so they opened all the blast-proof hatches between turrets and magazines, with the obvious danger that explosion could then travel down into the magazines and destroy the ship with one hit.
Convenenience so often trumps safety. The General Belgrano was sailing in waters its officers knew had enemy submarines in, and yet had not closed its internal watertight doors. This meant that it got sunk very quickly by 2 WWII vintage torpedoes.
Biting the hand that feeds IT
