Let's modify that, though: you can't expect to find anything there... except what's there. For instance, on our historical hashing of the Brookings, Oregon graticule last December -- the first time, I don't mind telling you, that anyone had hashed Brookings -- we happened on a field of scrap concrete and rebar!
Mrs.5000, for reasons that I was sure would become clear in the fullness of time, set about gathering the "best" of the twisted rebar.
...and behold, a few weeks ago, she constructed a garden sculpture.
So, there's another reason to take up geohashing. With geocacheing, you know what you'll find: the box. With geohashing, you never know what's going to happen. You'll probably end up with a garden feature or something.