Gold currently sells at $1200 per oz. Looks like smart watches are typically around 2oz in weight, though presumably a gold smart watch would be heavier. On the other hand, presumably also a large amount of the weight is non-gold. And you'd obviously pay a penalty for the cost of removing the non-gold bits and recycling the gold.

So, overall: The pure commodity value of the gold might significantly defray the cost of a hypothetical $5k aWatch, but not very much of the cost of a hypothetical $20k aWatch.