Now that you have spent three days exploring how object-oriented programming is implemented in Java, you're in a better position to decide how useful it can be in your own programming.
If you are a "glass is half empty" person, object-oriented programming is a level of abstraction that gets in the way of what you're trying to use a programming language for. You learn more about why OOP is thoroughly ingrained in Java in the coming lessons.
If you are a "glass is half full" person, object-oriented programming is worth using because of the benefits it offers: improved reliability, reusability, and maintenance.
Today you learned how to deal with objects: creating them, reading their values and changing them, and calling their methods. You also learned how to cast objects from one class to another, cast to and from primitive data types and classes, and take advantage of automatic conversions through autoboxing and unboxing.