Librarians will be better prepared to assist with the inevitable last-minute research needs if they know the background of the case and what has and has not already been done. The quality of research will be higher. Costs can be better controlled. They can help streamline litigation costs so that the firm and the client get the best and most reliable research for the least cost. Librarians are in the best position to coordinate some aspects of the litigation effort.
Librarians tend to have a familiarity with the work of all different parts of a firm.
There may be a brief or memo or expert depositions relevant to your case already in house that you don't know about, but your librarian just might. Some people think that the widespread availability of free computer databases via the Internet will mean the death of the library profession. However, information professionals, whether they call themselves librarians, or something else, are going to become much more important in the foreseeable future. Librarians can help screen, evaluate, and prioritize information, and alert their clientele to new and critical developments in their areas of practice. The Internet is a vast new research source, particularly for factual information.