Overloading properties is only one of the many useful things that can be accomplished with magic functions. It's also possible to perform additional tasks when working with the "isset()" and "unset()" PHP functions, but in this case by using another set of complementary functions, called "__isset()" and "__unset()" respectively.

In the examples he shows how to use the functions to see if a property has been set or to unset it and remove it from the object (could be helpful when working with private class properties).