[patates]

Allow you to open the app still and go through the menus, maybe you just want to export your data? Maybe you want to check the T&C again (which should be available offline from the menu)? Perhaps you wanted to see the design/ergonomics of the app before allowing it? It could be a thousand reasons. Photo app can display "No camera permission granted, click here to setup" instead of the visor or something, and the browser can also inform the user of the situation with a static page.

It's like proper exception handling: Do not just close the app, fall back gracefully and allow the user to retry.