If you set it, does it mean that the user will have an "old style" alert when a permission request is done?
There is no way for an app to opt-out of Limited Library, but apps can control when to show the picker.
Setting the Info.plist key tells the system to not automatically prompt the user to extend access and instead your app has full control over when to prompt to extend access.
You can call -[PHPhotoLibrary(PhotosUISupport) presentLimitedLibraryPickerFromViewController:] to show the prompt.
The relevant section of Handle the Limited Photos Library in your app is at 11m 49s.
Setting the Info.plist key tells the system to not automatically prompt the user to extend access and instead your app has full control over when to prompt to extend access.
You can call -[PHPhotoLibrary(PhotosUISupport) presentLimitedLibraryPickerFromViewController:] to show the prompt.
The relevant section of Handle the Limited Photos Library in your app is at 11m 49s.