With the new static keyword in PHP 5, is there any reason to use self keyword? I don't see any use-cases for it anymore
self and static mean two different things. See the documentation on late static binding. The first two examples demonstrate the difference.
In the context of static method if you wish to call another static method - you use self::anotherStaticMethod()
It is for static class members (access staic things in the same class) - that do not have a $this.