If you were one of many passengers and not wearing your seatbelt then you become a projectile inside the cabin. Wearing your seatbelt is important to the safety

If you were one of many passengers and not wearing your seatbelt then you become a projectile inside the cabin. Wearing your seatbelt is important to the safety of others. If you are on your own in your own car, I suppose you don’t have to wear the seatbelt. Same as not wearing a mask when you’re alone