Sure, you could just use a long branch as your walking stick. But would a long branch calculate how many calories you burn? Would it come with a built-in flashlight? How about a pedometer? I didn't think so.
Sure, $100 is a hell of a lot to spend on a walking stick, but who are you, a hobo? You need this stuff for a successful walk, don't you see? People in the olden days barely survived without it, so take advantage of the wondrous age you live in.