Sending batched IOCs to helix list

Hi, I have a large list of IOCs that would require sending them via API. What exactly is the difference between these two endpoints?

/api/v3/lists/{parent_lookup_list}/items/
/api/v3/lists/{parent_lookup_list}/items/import

The “import” one has parameter content type of “application/octet-stream”, so does it import the file as a whole?

Thanks!