What is the benefit to using an app to help you practice your interview skills? Is there some way the app could hurt your performance during an interview?

Want to shore up your interview skills while you walk the dog? Help is available for both Android and Apple devices with Job Interview Questions and Answers from Career Confidential. It’s an interactive video app to give you practice with “tough interview questions in an easy-to-use mock interview format.”
You can practice and compare your answers to suggestions supplied by a professional coach. Play Store also offers 101 HR Interview Questions from Programmerworld with 16 categories of questions.
With The SimuGator, an iTunes app with over 50 questions, users can experience various interviewing styles from different interviewers.