While not unheard of, silver cases are pretty unusual in watchmaking today. With much more durable white metals like steel and titanium readily available, watchmakers typically go in that direction, and then opt for  platinum or white gold when aiming for a higher-end execution. In a way, the relative rarity of silver watches is a pity, because silver has a warmth all its own, and it tends to patina in a way that many watch lovers, especially those who are into vintage aesthetics, would appreciate.