The minor nature of its goals is the whole point. It is not meant to do what we want because it empathizes with our values and is friendly, but because the thing we actually want it to do really is the best way to accomplish the goals we gave it. Also I would not consider making a cheese cake to be a trivial goal for an AI, there is certainly more to it then the difficult task of distinguishing a spoon from a fork, so this is surely more than just an "intelligent rock".