What documents need to be added to the FamilySearch Memories?

From time to time the issue arises as to what should and what should not be added to the Memories section of the FamilySearch.org website. There is an initial issue as to the distinction between "photos" and "documents." Photos contain people and places. Documents have words and information beyond what is depicted. The difference is a matter of opinion to some extent. If an image is added as a photo, it can easily be moved to become a document by simply checking the box provided in the Details section of the program. Here is a screenshot showing a photo with an arrow showing the Details section link and another arrow indicating the check box.

This option will only appear if you are the person who contributed the photo. 

This still leaves a question as to what should be added as documents. There are a significant number of people who feel that copies of U.S. Census Records should be added as well as copies of any other source documents that are discovered. The supporting argument for this position is that the document may not be available in the future and it is a good idea to add the document to the Memories section so a copy is always available. I guess my counter argument is that those who add these documents almost never provide the full citation to where the copy came from. I guess the question is really moot, since we do not (yet) have the ability to edit any of the Memories provided by others except to add tags and other such additional information.

I do suggest that those adding any type of memory check to see if what they are adding is a duplicate however.