If it's anything like on Android, where you just give it blank permission to access your entire storage, it would be useless. There are plenty of programs you might want to use that have no business having access to everything, that you can't or don't want to trust 100%, but it's easier for the developers just to ask for everything (or it's the only option).

The "ask for permission" model is broken.

Everything should be sandboxed without giving the application awareness of being sandboxed. If you want to give additional access to a program, it should be through an external interface only accessible to the user.