Does jettisoning that weight have a tremendous impact on cruising efficiency? My impression is that the main advantage of dumping a take-off battery is reduced

Does jettisoning that weight have a tremendous impact on cruising efficiency? My impression is that the main advantage of dumping a take-off battery is reduced landing weight, which is certainly an issue with existing commercial jet airframes. They can't land with a full fuel load without damaging the plane. But I'm not clear on what affect it has on range/efficiency.