British and German battlecruisers optimized for different seas

Why did German battlecruisers generally have stronger protection than British designs?

Germany optimized for a shorter-range North Sea fleet and battle-line combat, while Britain paid more weight for global endurance and speed; the designs answered different strategies.

Royal Navy battlecruisers had to operate across a global network, so fuel, endurance, and sustained high speed consumed displacement. German ships were designed for a more concentrated North Sea war and could devote more weight to subdivision and protection. Their concept approached a fast battleship because the vessels were expected to reinforce the battle line as well as scout. Tiger represents the most mature British prewar balance, but the two traditions still reflect different strategic requirements rather than one navy simply understanding armor better.