Essay-writing skills are more important in some careers than in others. An essay may be defined as "a piece of writing which is often written from an author's personal point of view."
Someone whose working career is spent in retail sales, for example, may not have frequent reason to write work-related information in the format of an essay with a thesis statement, body paragraphs containing supporting details, and a summary conclusion.
Someone employed in a field directly concerned with some type of communications (such as a reporter, author, researcher, or technical writer, for example), would need to be proficient at organizing ideas and words so as to clearly convey the information being presented.
In some careers dominated by use of written language, it would be important to understand how to present one's personal opinions or interpretations as part of the written product; in other careers, it would be critical that the writer was able to maintain an objective point of view and not incorporate opinion into the piece.