From working on warehouse picking software way before there were robots ... it's because humans. It would take longer for a human to find space in the right spa

From working on warehouse picking software way before there were robots ... it's because humans. It would take longer for a human to find space in the right space -- or instead, be lazy and forcibly put an item in a space it barely fits -- than to simply dump it into an arbitrary box with enough space and record the box. Then when deciding the path for the picker to pick items from, there's a high chance one of the purchased items is actually nearby other purchased items.