Imperial fast battleships restate the historical logic of the battlecruiser. Speed is valuable because it lets a lightly protected heavy ship choose the range at which its guns and armour are most favourable. It can also decline an engagement that has turned against it. Placing that ship in a line with slower battleships removes both freedoms and exposes its reduced protection without using the advantage for which it was designed.
Notable Point · 1:07:20-1:08:35
Battlecruisers lose their speed advantage in the line
A fast capital ship cannot dictate range or avoid action once doctrine fixes it inside a conventional battle line.