They would be terrible martial prowess. Primarily because gold is soft. While it is unlikely a sword will 'just slice through them' they will dent easy. If all the gears are gold, a little extra stress and the teeth will start striping, cogs without teeth are 'frictionless' wheels. Good dents in the armor will also interfere with the inner workings.
My ring is an alloy and I've distorted it working in my shop with hand tools (while I was wearing it!) Pure gold is just to malleable. And if you think of making it thicker to handle stresses, you will run afoul of the square cubed law. The weight of the armor as it thickens will put a lot more pressure on all the working joints and cogs. Swinging clubs at reasonable speed is about what you'll get, expensive cave men, that can break themselves if strained too hard.