They are used on some compact digital and video cameras (camcorders).
These lenses make it easy for a photographer to aim a camera without moving around too much.
In contrast, swivel LCDs (also known as articulating screen) are displays that freely rotate while attached to a camera body.
Usually, the camera body is much larger than the swivelling display.
Some cellphones have lens that rotate and allow users to take self-portraits but are limited in the angles where the camera can take pictures.