Common interview question: Why should we hire you for this job?
Why they're asking: They want to make sure you are confident that you can do the job and prove that you are the right person to do the job.
Why it's tricky: It's a very open-ended interview question. It's also sort of a bold question, one that is kind of meant to challenge you a bit and see how you respond to pressure.
How to answer: Explain why you're great, what you've done that relates to the job opportunity, and be really, really confident.