PWAs can never fully substitute native applications. It's difficult to access hardware and impossible to call operating system functions from a PWA. Applications that do something interesting tend to have a native library behind the frontend that does performance-sensitive work.
Quite the contrary, one of the benefits of PWAs is exactly that when they are distributed via app stores they get access to native APIs without any kind of manual FFI.
That is how they work across ChromeOS, Android and Windows, with Apple being the outlier for obvious reasons.
I didn't know this. If this is true then it's more powerful than Electron, which requires you exchange IPC messages from a separate process. The fact that you have to use the app store is a major disadvantage though.