Why Britain might have used a cruiser Germany did not need

The Royal Navy needed hulls across global sea lanes to protect millions of tons of shipping, hunt submarines and surface raiders, and maintain presence. Before convoying reduced some of that burden, even an old cruiser could fill a patrol gap somewhere in the worldwide system. Germany faced the opposite design problem: a raider leaving home waters had to evade or pass Britain before reaching likely targets. Gefion's 19.5 knots and limited endurance therefore made her much less useful to Germany than the same hull might have been to a navy with global defensive commitments.