The phrase represents a request for clarification and justification. It seeks both a definition of a subject and an explanation of its value or relevance. For instance, one might ask this question about a complex mathematical concept or a newly introduced business strategy.
Understanding the essence and significance of a topic is crucial for informed decision-making and effective communication. A clear explanation fosters comprehension, enables application of knowledge, and facilitates meaningful discussion. Historically, this type of inquiry has been fundamental to scientific progress, philosophical debate, and societal advancement.