Think of them as your own personal shopper for matters scholarly. Purchasing Services will get you obsolete tractor paper for your department's antique printer, or a crate of frogs for your next departmental party, or even your lab, if you're into that kind of thing.
Professors aren't the only people in the classroom who are key to the university classroom experience. Teaching assistants often put as much work into their job as a full-time professor.
Macdonald campus in Ste. Anne de Bellevue was created in 1907 to improve the lives of rural people in Quebec. That mission remains, but the cutting-edge technology has changed dramatically.