But the work is in the direction of the force, and it isn't the crane pushing the material down. It's gravity.
Gravity is doing the work.
If the material was being lowered by a cable wrapped around the shaft of an electric generator, then you could use the work done by gravity to generate some electrical energy, and then sell the energy.
Or, if the "material" happened to be water, you could let gravity lower it through a turbine or a water wheel, and use the work done by gravity to grind wheat.
Yes, the crane may be raising a sweat, working against gravity. The purpose is only to prevent gravityfrom doing the work too fast.