When an experienced character becomes very effective at fighting, it takes less than 10 seconds and 15 mouse clicks to kill a horde of more than 15 Zombies, less with firearms. But then it takes ~30s to loot them all and even more when corpses have dropped on top of previously killed Zombies. Also this includes a lot of clicks and drag&drop actions.
For some of us players, the time spent to loot is neither challenging nor interesting.
By looting or dropping on ground automatically your selection of loots, you reduce a lot the time spent and you reduce to ~nothing the number of mouse actions involved in the looting process.