Running $apply on $rootScope vs any other scope

Question

The $apply function can run on any scope, including $rootScope.

Are there cases when it makes a difference if I run it on my local scope or

Answer 1

Another reason for running $apply on the $rootScope instead of $scope typically comes for me when I need to call $apply in a service which will be used by different controllers and therefore different scopes.
In this cases I prefer to inject the $rootScope to the service and call $apply on it without worrying on which scopes the service will be used in the future.