Glad you asked. Unlike Liability coverage, Comprehensive & Collision coverage takes care of your vehicle.
Collision coverage will cover damages to your vehicle in an accident regardless of fault, this also includes hitting an inanimate object like a mailbox or light pole.
It also covers your vehicle in the case of a hit and run or an accident with an insured motorist, however your policy must include uninsured motorist bodily injury coverage to cover any personal injuries.
Comprehensive covers your vehicle for non-collision related incidents such as theft, vandalism, hail, falling branches, etc.