Standalone Documents - Why does SFC only allow the creator to send a document?
Documents and more specifically the Standalone/Referring documents don't have a workflow and without transaction between MS nodes, because this is more flexible and more convenient for users and best reflects how document transmission in most organizations work.
The only type of status is sent or not sent, so a creator cannot indicate that he finished editing the document, that he uploaded all the necessary files, and that the document is ready to be sent. If we would allow someone other than the creator to send, this person could send incomplete documents.