I asked the question earlier, and maybe it just sounded like I was being my usual sarcastic self, and didn't sound like a serious question. I really don't understand the utility of BF measurement. What difference does it make?
Sorry for reviving a dead thread, but finding out my BF% was useful for me. I had a DEXA done to find out my bone density and, as bonus, was informed of my BF%. Turns out it was < 4%. I had no idea I was so close to having a dangerously low BF level, and I've been eating a lot more since then.
I just assumed I was at ~10% +/- 2-3% because pictures of bodybuilders who have < 5% BF always have giant bulging veins, incredibly well defined muscles, etc., and I didn't see that in myself when I looked in the mirror. I guess all that pre-contest stuff bodybuilders do makes more of a difference than I thought.
I compete in a sport where performance is heavily dependent on strength:weight ratio (climbing), so I still try to keep my weight down, but my performance has improved tremendously since letting my weight go up a bit (as have my numbers in the gym, although I don't really care about those).
As you say, there are other ways I could have found out that I was at a sub-optimal weight, but getting a BF measurement is easy, so why not?