This is the academic honor society for nursing. It means that your GPA is good, and that the faculty that invited you to apply/be inducted see something worthwhile in you. If you plan to go anywhere with your career, or to teach, or to write, or to do research, it is a useful feature on your resume. It can be a good networking resource. Importantly, if you have the chance to join during school, do so and keep your membership active. After you leave school, in order to join you must do so as a "community member," which requires five years experience and a nomination from a "somebody" in the local chapter. Overall, it's a good thing to have on your academic and professional resume, and can help you access the academic/research sides of nursing. If nothing else, you get a subscription to a research journal, so you can talk knowingly about current research trends with your colleagues.