Earlier quoted context omitted.
It really doesn't make sense. By that logic, I shouldn't be allowed to load web pages because it's impossible to secure a browser. PWA's only need a few extra integration privileges like badge- and window control, rest is just a web as usual. What you link is a case of one app (edge) reading the data of another app (chrome), which is entirely unrelated to PWAs.
> By that logic, I shouldn't be allowed to load web pages because it's impossible to secure a browser. Indeeed, and 'whatever browser engine you picked here' is responsible for correctly implementing these additional security features. That's the argument; if you write an app that lets you run other apps inside it how do we make sure your app does security correctly? When you look at it from that perspective, you can…
Yes, and Apple now (against their will) allow me to select this browser myself to browser the web with.
Whether I use this to load a webpage normally or as a PWA does not change the risk I was exposed to. PWAs just let a web application ask the browser to run "fullscreen" without browser chrome, to set its badge and colors, to register as a handler for certain URL types, and to open the share panel. All actions already taken regularly by said browser.
Even if we assume Apple's statement that other browsers are insecure is correct, there is no value in blocking PWAs and requiring me to instead use bookmarks: I am still loading said application in said browser that implements and uses all this functionality itself. To the OS, a PWA is nothing more than a type of bookmark for a browser.
So, no - this is not reasonable and their argument makes no sense. If it was true that Safari was actually safer, then Apple should instead spend energy sharing how so that other apps can be equally safe - it would be incredibly irresponsible for the platform owner to keep security as secret sauce - rather than handicapping other apps.