Tail surfaces or engine fittings also fail. The frequency of these events increases as aircraft grow older. Due to low production rates in the last two decades, a great many airplanes are 20-40 years old. But all pilots stray from safe havens occasionally, as when crossing a mountain range. If the terrain is too hostile to permit a safe landing, a BRS could save the day.
Pilots make judgment errors.
If you need to stop that plane quickly after landing on a slick surface, a BRS may help. In less than one second, the rocket will extract the parachute and will stretch tight its lines and the airframe harness attachments. The aircraft stabilizes under the canopy quite quickly. The altitude required is a function of speed more than height. It depends on what is happening to the aircraft at the time the parachute is deployed.