I’m not, I guess the difference is animation vs UI? From the article, the ios library is set up to run animations off thread on a render server.

>On iOS, the most performant and power-efficient way to play animations is by using Core Animation. *This system framework renders animations out-of-process with GPU hardware acceleration.* Animation playback is managed by a separate system process called the “render server”. This means Core Animation-powered animations don’t contribute to the CPU utilization of the app process itself, and can continue even when its main thread is blocked or busy.