They know how to configure a keyboard for Spanish characters and which electronic foreign language dictionary is the best. They know what is truly important to the discipline and what is fluff. OCs understand the personalities of their customers. They know who wants to be pointed to the manual and who needs to be shown. They know who is too shy to ask for help and who is facing a high-priority deadline.
Departments can best weigh costs against benefits for their constituencies.
If a completely customized desktop environment is essential to a department's success, it can reallocate existing personnel to provide for it. If it is not essential, the department can take advantage of the environment provided as part of the institutional infrastructure. Departments can decide when a particular technology should be introduced, and to what extent. If only one person wants a Web page, that can be dealt with one on one. But if half the people want Web pages, it may be more efficient to provide a class.