I just moved a couple of items from 2017 to a new document, and all those items now have Created Date set to the moment I moved them.
I understand the logic: this is the moment they were created in this document, but I think it’s semantically more correct if items that are being moved would bring with them their own historical information. For some items it’s quite important for me at times to know “this was originally created then and then” versus “this was moved here then and then”