Exactly, that's always what they wanted it turned out. It's easy to say that 19th century Europe was reshaped by Napoleon, because he seized control of France from the fledgling republic and invaded all of Europe. But how did he do that, why is it different when Napoleon did it from when previous European powers invaded each other. Are there any other people or armies to compare him to, and how were they alike or different. What tactics did he use. What were the long term effects of all of this.

This is the opportunity to not just say that you know the answer but to explain that you understand the context within which the question and answer reside. To demonstrate an understanding of the material. Sure some essays are bad essay questions, and I think some teachers really suck at explaining what they want out of an essay, but most of them just want that.

History in particular really needs essays to be taught well because short answer, fill in the blanks, and multiple choice questions can struggle to test the understanding of the whole picture and can leave people thinking that Frederick the Great is just some king who was good at war in the mid 1700s and not a vital piece of a story that eventually results in two nuclear weapons being dropped on the Empire of Japan.