The question What's the point of checking in several days before a flight? was closed as opinion-based. Why? The existing answers show there exist objective reasons, e.g. seat selection or increasing the likelihood to board the flight in case of overbooking. Most close votes were cast after the first objective answer was posted.
From the Cambridge dictionary: opinion = a thought or belief about something or someone.
From https://travel.stackexchange.com/help/closed-questions:
Opinion-based: discussions focused on diverse opinions are great, but they just don't fit our format well. Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than on facts, references, or specific expertise.