Did they ever try domesticating them? What about milking them? Were they only used as a food and material resource?
Buffalo and bison are different species of animal. Assuming that you actually meant bison, the National Park Service (NPS) says that a bison's temperament is unpredictable which makes it very difficult to domesticate them. They may "appear peaceful, unconcerned, even lazy, yet they may attack anything, often without warning or apparent reason."