Interesting to see Safari adding JPEG XL support just as Chrome dropped it:
This seems like a strange decision.
1. Auth with local storage can be quite nice if you don't need to send the cookies to the server on every request.
2. This will lead to different login states in the browser and in the "app" which is not what I would expect and can be inconvenient if you open links to that website.
With the `SameSite=strict` option on modern browsers and the `HttpOnly` (plus `Secure` to only run in SSL secured context), Cookies are more secure and the way to go instead of storing credentials anywhere accessible from within JavaScript. Before SameSite=strict, cookies were a security nightmare and often resultet in XSRF attacks, and required XSRF mitigations (like xsrf tokens), but this is no longer the case as all modern browsers support it.
As for your (2) point, I think cookies is the only thing that should be copied. LocalStorage or IndexedDB could result in inconsistwncies and breakage (PWA and Website code can version missmatch).
Not a lie, but they leave out an important part: To have webpush or badges on iOS you need to "install" the web app - but since iOS PWAs block custom install buttons, the user had to know thst he has to push "Share" and "Add to home screen". To my experience, almost noone knows this or does this.
Who is consenting to these? What is their deal? It makes no sense to me.
So there has to be a tasteful user notification informing them that the site has enabled that feature in the manifest?
Neither works for Safari/iOS. The only way to help the user, is to show a step-by-step tutorial how he has to navigate his iOS Safari to install. And on top of that, nothing is shared between the installed PWA and the Safari instance - always requiring the user to re-login after install. It is just poor UX.
Based on Web Platform Test [0], it looks like Chromium browsers are not performing any better in this area.
[0] https://wpt.fyi/results/css?label=master&label=experimental&...
But I feel the pain of having to carefully test 2D/3D transform and animation on all browsers across platforms (even Safari on iOS and macOS can have different behaviors).