I disassemble all wheels which have non-anodized rims because I can get a much (MUCH) better polish with my buffing wheel than by hand. Those who say you don't save any time or effort are right but for me the results are worth it, even on bikes I'm going to sell.
Also, I'm not too sure about plated spokes, but the old bare-steel ones will clean up with fine steel wool soaked in phosphoric acid. That's really unpleasant so I only do it when it's important to keep the original spokes.