I mean for if you need to create child items, or do other logic
bulk create is fine for a duplicate but it is very limiting for create from list.
for instance I often will create things from a list of option sets - create 1 item for each option.
but there will be conditions applied so I may only want to create the option if XYZ - and those conditions may change or have multiple filters per option set - so each option needs to be evaluated, and then each option may need to trigger other things to happen - basically I rarely find a use case for bulk create other than to duplicate existing items.
and the cost savings of using bulk create vs just the schedule api on list are minimal for most apps - most wu costs are in repeating groups, searches on pages etc