After spending 10 years as a software developer, I have gained experience in both executing and going through interviewing processes. The reason why many applicants struggle is that they rarely get feedback they can use to improve their skills.
Even though I personally disagree with not giving feedback to applicants, I can understand that this is how the world works and this is what we have to accept. By asking for feedback, you maximize your chances of getting feedback.
The mental side of interviewing is also ...