Silver aluminum--why so rare?

[OhYeahWatchMe]

In my visits to Apple stores and other Apple Watch sellers (Target and BB), I've seen various aluminum and SS series 2 watch cases but the one option I have NOT been able to find is *silver* aluminum. Have others noticed this? Why is this particular option so elusive?

 

[44267547]

The silver aluminum is not exclusive by any means. It's just the most Popular color in offered in Apple's cheapest Series in the Apple Watch. Compared to the stainless, which is significantly more expensive.