"In my humble opinion" Classifying is a fantastic tool for improving your stock. It gives you a non biased look at your animal's faults (yes, they have them!) and strengths (they have these too!) which can help greatly in looking for particular traits to improve. e.g. if your cow shows up as being narrow in the pins, or lacks depth you know to look for a bull with wide pins and plenty of depth.
It also is a great check to see if what you are wanting to improve in your herd is actually happening (what you are wanting is for daughters to classify higher than their mums or at least not go backwards).