Also, of course we have perception of droplets. What we don’t have is an intuitive understanding of how light interacts with droplets.
I suspect that Apple are trying to leverage this lack of intuition to make their ui interesting to look at in an evergreen way. New backgrounds mean new interesting interactions. I’m not confident that they’ve succeeded or that that’s actually a good goal to have though. I have it on my iPhone 13 and personally I find it annoying to parse, and I feel relief when I go back to traditional apps untouched by the update like Google Maps