It's also only 45 frames uncompressed at 4k. It's remarkably easy to hit that if your base assets are mostly raster rather than vector for a dynamic scene.

Obviously, they should try harder, and this is an explanation rather than an excuse, but the graphics assets are mostly why.

Why would you need that kind of resolution for a weather app? What are you even going to depict with all those pixels?

Because people are looking at it on 4k screens.

I mean, I usually check the weather by putting "weather" into a search engine. And this will show me little SVG icons that take up a tiny fraction of my low-resolution screen and probably involve like less than a kilobyte of path description. And I think this looks perfectly fine and I can hardly even fathom why anyone would want it to be fancier than that. I think that even animating them would make the display actively worse.

I have deep faith you can find the imagination with in you to understand