I understand, and I agree. But in this case it's not that anyone will care or notice... it's that it is completely irrelevant. There is absolutely no way that anyone who does care would be ABLE to notice that the watch faces were developed from such high resolution source images.
Whether they use 1000 x 1000 pixel images or 90,000 x 90,000 pixel images... when they are rendered to 390 x 390 there is absolutely no difference... it becomes excess for the sake of excess.