Why Furious's forward flying-off deck became obsolete

Did the lower flying-off deck on HMS Furious and her sisters ever become obsolete?

Yes. It was useful for rapid fighter launches at first, but aircraft growth overtook it and the area became an anti-aircraft position.

Furious's forward deck let fighters launch quickly while the main deck was being rigged for a strike or recovering aircraft. The arrangement anticipated the later desire to separate launch and recovery cycles that encouraged angled flight decks. Growth in fighter size and takeoff requirements eventually made the short forward run unusable. Once obsolete for aviation, the space became more valuable as an anti-aircraft position.