What is the purpose of a seatbelt?

The purpose of a seatbelt is fundamentally about safety. It is designed to keep occupants securely in their seats during a collision, significantly reducing the risk of injury or death by preventing ejection from the vehicle and minimizing the chances of the occupant colliding with the interior of the car or another occupant. In a crash, the forces can be immense, and without a seatbelt, passengers can be thrown around inside the vehicle or out of it entirely, which greatly increases the risk of serious injury.

While other aspects of driving or vehicle operation might enhance the experience or efficiency, they do not relate to the primary safety function of a seatbelt.