Object-Oriented, well, ang pinaka simpleng purpose nito ay to make your code Efficient, Secure and Extensible. Efficient in the sense that you write a code that is easy to maintain, readable and reusable. In that case, anybody(any programmer) can understand and handle your code. You can even share your code with your co programmers with OOP via library or API or yung pinaka basic, dll. Secure in the sense na, you promote the basic principles of OOP which are Ecapsulation, Abstraction, Inheritance and Polymorphism. Huge libraries and frameworks promotes these things like Entity Framework and Nhibernate. These are frameworks to speed up development and its core function is to encapsulate how data is being persist/manipulated from and to the databases. Extensible, from the word itself. Imagine you need to expand your application's functionalities or features? that will require additional codes and even colleagues to make it done. How? jan na papasok ang Objects which is the most basic component is the Class. You make a routine, variables, methods, properties, enumerations, etc which are all a Class' members and extend it to a different classes within your projects. With classes, extending and reusing code is very easy and can be implemented at ease. Mas magiging madali ang colab at coordination ninyo ng co programmers mo. So thats it! OOP is a paradigm or a pattern that will make you work efficiently in a programming environment. Mahirap at komplikado sa una pero, pag nakuha mo na ang concept, its very easy. Kung ako sayo, dahil mukang estudyante ka pa lang naman, aral lang ng aral. Wag mo munang intindihin ang OOP lalo na kung wala ka pa sa subject na yan. Mata-tuckle mo din yan sa college days mo. Procedural ka muna. Then practice logic formulations and analytical enhancement. In the course of your learning maiintindihan mo din ang OOP. Promise, madali lang ang principles ng OOP.
Good luck!