Interviewers often ask if you would like to add anything because they want to allow you to share any additional information that you may not have had the chance to mention earlier in the interview. If you feel like there's something important you haven't mentioned yet, it's always better to bring it up rather than regret it later. A great way to do this is to say something like, 'Thank you for asking. Yes, I wanted to add...' and then share your thoughts. This is your opportunity to ensure that you have fully expressed yourself and highlighted your relevant skills and experience.