An interviewer asks personality questions to gauge your soft skills and various other aspects that your technical and professional experiences don't reveal about you as an employee. For example, with a personality question, the interviewer is able to understand your teamwork, work ethic and aspirations.
You are more than just your skills and accomplishments, and a personality or opinion question is an opportunity for you to demonstrate that! For example, the answers to these questions speak a lot for your creativity and inspiration. An opinion question presents you an opportunity to share a profession opinion. These types of questions can differentiate you from other candidates.