There are people who genuinely believe they are good at their job, when they're not. They're not bullshitting and the conversation is genuine.
Just 10 minutes of coding (or attempting to), tells you they can't code. A little longer can tell you roughly how good they are.
Experienced developers who can code have had the misfortune of working with people who couldn't pass this, and may appreciate that the members of their new team can.
Where do you fit?