I don't see how this refutes GP's point. Yes, it's a big challenge but when they are allowing other browsers, the challenge is met already. The "install to home screen" feature adds but very minute extra features.
My understanding is that Apple can provide security guarantees only for their own browser, because it's tightly integrated with the rest of their stack.
I guess the issue is that PWA is more deeply integrated… so instead of having this integration within the OS using their WKWebView component, they need to make it a user choice which browser component is used.
This component then has to be installable through the App Store.
This then also means an ‘app’ is hosted by another ‘app’, and to do this properly that host app needs to many permissions
