Why submarines experimented with gyroglider scouts

If helicopters existed during the Second World War, why were they not widely used from warships?

They remained experimental and did not become broadly practical naval tools until the 1950s and 1960s, although Germany fielded a collapsible towed gyroglider for submarine reconnaissance.

Several rotorcraft types existed before and during the war, but their reliability, payload, and routine serviceability were inadequate for widespread fleet use. The German submarine gyroglider addressed a narrower problem by lifting an observer high enough to see beyond a U-boat's very low horizon. Its sections had to be brought on deck, assembled, tethered, and flown by a particularly exposed crewman. A pressing reconnaissance need produced a specialized aviation solution without making helicopters generally practical at sea.