Where British battlecruisers offered strategic value beyond the Grand Fleet

How strategically alarming would a battlecruiser with unlimited range have been before the First World War?

Very alarming as a global counter-raider and mobile heavy unit, though its pressure on Germany itself would be limited once British blockade had already cut German trade.

British battlecruisers did not primarily frighten Germany by threatening trade once blockade had already severed it. Their value lay in defeating German surface raiders and rapidly projecting heavy force elsewhere. Some classes might have been better retained for worldwide hunting, Mediterranean support, and operations against the Ottoman Empire instead of concentrating every fast capital ship with the Grand Fleet.