Traditional programs are centered around the processes and procedures that the program is trying to model. Object-oriented programs, on the other hand, are centered around the real-world objects that the program is trying to model. Once these objects have been identified and modeled, we can write programs that use these objects to simulate the processes and procedures in a much simpler and cleaner way than other programming approaches would accomplish.
If we base our applications on business objects then we'll create a collection of reusable building blocks that we can use time and time again in applications throughout our business. And, perhaps more importantly, we can continue to change and evolve our objects, over time, with little or no impact on the older applications that are already using those objects.