Cameras that look like a pocket watch are not usually rare but recently a Lancaster pocket watch camera sold for £17,000. Wow !
It was small (2×1.5 inches diameter) and was nickel plated (not gold). It had a six part sprung telescopic lens and a sprung brass drop shutter. The camera had an engraved case referring to J Lancaster & Sons.
I imagine that the price reflected the fact that two very wealthy buyers fought a long battle for it. It is not always the case that competition exists and without it prices can flounder.