Luxury Lite makes a hiking staff called the Big Survival Stik. www.luxurylite.com- It is aluminum and carbon fiber, and breaks down into segments. One segment has the aluminum tubing sharpened, and this can be mounted on the point of the staff for use as a spear! It was reviewed here on BPL a while ago, including live-action video in spear mode, and referred to in jest as a "trail defense system".
I have one, actually- I bought it before I went UL when I was still trying to figure out my personal hiking style. I still carry it when hiking with my wife and daughter for two reasons: 1) They slow me down, anyway, so no worries about making mileage, and 2) the staff seems more useful than would a trek pole for fending off coyotes or catamounts should one decide to have a go at my little girl.
Most people acknowledge that trek poles do have uses for trekking. If you use the Nordic walking technique (which most people do incorrectly) they can help you make better mileage, but unless you are really into that then, yes, IMHO they really only have utility for keeping your balance on unstable terrain, saving your knees on long downhills, etc. Many people don't consider them worth the bother. I have found that I do like them, but mostly because I like scrambling rather than hiking maintained trails.