The need for a feed back is mostly psychological need. You go in, you think you did well, but you didn’t get the job. The company of course found someone better than you, some one did even better. Most likely the feed back won’t help you on your next interview, and second you just need to read most of the writing which is already on the wall. If you failed a white board, you’d know it. If you aced the white board som…
- your CV could have undersold much of your expertise - you may have come across badly in the interview for multiple reasons, from shyness to overconfidence - you might not have prepared sufficiently for that specific role in that particular business in some way - you might have acted in a way which gave the impression that you were immature or unprofessional, from your attire, body language or communication style
Any feedback which can help you improve selling yourself and make a better impression is useful.