The CameraComponent adds a camera perspective as a sub-object to an Actor. The CameraComponent will provide information about the camera's properties if the ViewTarget is a CameraActor or an Actor that contains a CameraComponent and has its Find Camera Component When ViewTarget option set to true.
For example, you could use CameraComponents to switch between multiple cameras in your level during gameplay. By using Set View Target With Blend and a CameraActor, you can switch between each of your cameras and use the properties that you define within the CameraActor for each camera (including field of view, angle, Post Processing effects, etc.).
A related property that can be set for any Pawn is Take Camera Control When Possessed, which causesu the Pawn to become the ViewTarget automatically upon possession by a PlayerController. So, for example, if you had multiple Characters (which are a form of Pawn) that you wanted to switch between, and each of them had their own CameraComponent assigned to them, providing the camera perspective to view from, you could set Take Camera Control When Possessed to true for each of them and whenever you switch between them, the CameraComponent for that pawn would be used.