Like LA Times and Al Reuters:
Photojournalism in Crisis (Dinosaur Media DeathWatch) (Editor & Publisher August 18, 2006 David D. Perlmutter)
Those negatives used to provide a "paper trail". Negatives were even used in the OJ Case to show a historical timeline that OJ owned such a pair of shoes.
The out takes file was also responsible for finding the photo of Bill Clinton hugging Monica at some point.