From LLRX:
If you look at FOIA litigation in only the context of who ultimately wins a case, you would come to the conclusion that the government routinely is the complete victor. That conclusion, however, would be wrong.
The results of FOIA litigation are much more than just a judge’s opinion for one of the two sides in the case. Bringing a FOIA case often results in a more timely release of information, more information being released then the agency would have released if it wasn’t in litigation and more information going to the requester about agency decisions and withheld documents.