The biggest advantage that a wooden, non-folding wading staff has over the folding aluminum ones is not the stealth factor, though, it is that it will not be folded and holstered on your belt when you start to fall. I don't care how fast a draw you are, when you have started to fall you will not have time to deploy your staff before it is too late. And funny as it may sound, you don't always know you are going to fall ahead of time!
Most people with the folding staffs only seem to use them in deep, fast current, but consider this: The rocks are just as slick under 2" of water as they are under 2' of water. If you slip and fall in knee deep water you'll get wet. If you slip and fall in ankle deep water you can break rods - or bones.
That's a very good point and why I make a conscience effort to keep my folding staff (Simms) deployed until I am safely back at camp.