The cookie/session isolation is underrated. Half the reason services push you to the app is because the mobile browser experience for juggling multiple web apps is genuinely bad — not because the web can't do it, but because nobody's made it comfortable. I got annoyed enough to put together a small webview manager that keeps a few web apps in tabs with separate cookies: https://github.com/theoden8/webspace_app (yes, it's written in flutter)