What is the utility of the design pattern Observer when you can get the same results without using it?

I'm aware of the use of the pattern observer but for the moment I'm seeing that it's a useless layer to do operations on observer objets while you can do the same operation without the need to use this design pattern !

Can somebody correct me if I'm wrong and explain to be using a concret example the utility and the importance of this design pattern ?

I can see that it offers more code organisation but when should I use it ?