A short interview offers only a narrow view of how someone might work in a real team over time.
An interview compresses a complicated judgment into a small number of conversations. It can reveal how someone explains an idea or responds to a question, but that is only one setting. Actual work involves ambiguity, follow-through, changing priorities, and decisions whose consequences arrive later.
Those qualities are difficult to observe in a short meeting. A polished answer does not guarantee ownership, and a hesitant answer does not tell the whole story either. Hiring has to rely on limited signals, which makes the process imperfect even when everyone involved is trying to be thoughtful.