Mostly to benefit weaponsmiths that want to arrange their inventory (make piles of metallic items sorted by type of metal), it would be useful to implement the filtering option already present in the normal drop command. It would also help getting rid of undesirable herbs faster if the character has a sizeable inventory, or stashing specific item sets that drop all of one type doesn't cover (i.e. dropping medal and crown of chaos in one turn without having to search your inventory for it manually).