My experience when I gained mine was that it is more about achieving a standard and having achieved it, undertaking personal development to ensure that you maintain that standard; if you like you grow with your chosen profession; that development can be costly and in my case I'm lucky that my employer chooses to support me.
As to what the benefits are; directly - I didn't get paid any more, I can't part seas or stop speeding locomotives with a single hand. It has helped me understand that while I almost always have an opinion, I don't really know everything and there is always a different and potentially more productive way of doing things.
