Sensor wear
This does not happen AFAIK. Most phones have no shutters so tge sensors receive light all the time, and the little required power does not overheat it.
mechanical parts (if any)
This is a valid point but the actuators in a phone camera's focusing mechanism are more like a speaker than a motor. They can last for ages, and many apps allow disabling autofocus when idle.
heat
This one is valid. Even basic image processing is a load on the CPU, and recording/streaming definitely is. Depends on how the camera is mounted to allow airflow.
gamble and see how long it lasts
Sure. The stakes are not very high if the phone would otherwise lay in a drawer.