Your interviewer knows you are looking for a job. But one of the primary aims of an interview is to determine why you are looking for a job. Are you looking for any job anywhere because you don't get along with others at work or are trying to earn more money, willing to take the job with the best offer, or are you career-oriented, looking for a culture and work environment better suited to your values, goals, and potential? These questions are often answered by asking why you are pursuing a job with them. However, asking why they should hire you helps them determine your understanding of their goals for filling this position and what they are looking for in their ideal candidates. Consider this question as another opportunity to offer your pitch on why you are the right candidate for them and how you stand apart from the others.