People aren't being dismissive. The point is that whether someone is intelligent and hard working is utterly irrelevant to everyone else, especially in a work environment. What matters are results, not inner qualities.
That rather depends on the job. Punctuality = productivity for many jobs, especially those in manufacturing, food service, agriculture, education, hospitality, transportation, security, etc. In the real world certain things have to be done on set schedules and anyone who can't reliably show up on time is worse than useless to those employers.