Postgres might have been a perfect answer, but the candidate needs to explain why and how.

The purpose of the interview is for the candidate to demonstrate their thought process and ability to communicate it. “Just use Postgres” doesn’t do that.

This would be more obvious if it was a LeetCode problem and the candidate just regurgitated an algorithm from memory without explaining anything about it. Yeah it’s technically the right answer but the interviewer can’t tell if you actually understand what you’re talking about or if you just happened to memorize and answer that works.

Interviews are about communication and demonstrating thought process.