But that will cause some input doesn’t work, such as the moving by the keyboard in FreeCamera, having a look https://www.babylonjs-playground.com/#UNB24W#13, moving by the keyboard (arrow keys) doesn’t work, after uncommenting the camera.update(), anything works well.
After searching the source code, I found keyboard inputs checking (camera._checkInputs()) only called by camera.update():
So I think camera.update() is needed.