The problem at the time was multifaceted. The devices couldn't handle it, the network couldn't handle it, and webkit was still relatively limited. But it did work. https://9to5mac.com/2021/06/03/remembering-apples-sweet-solu...
Performance isn’t incredible, but neither is the “native” app (95% sure it’s react native or similar), which frequently dips below 60fps.
MacOS is getting there kind of lately with safari being able to turn web pages into apps. But there isn't really built in mechanisms for that: https://www.macrumors.com/2023/06/14/how-web-apps-work-macos...