Implementing QCameraImageCapture::setCaptureDestination(CaptureToBuffer) would be nice for applications that need to exploit the captured image after it has been taken.
Examples range from computer vision applications, applications that doesn't need to save images to the disk (directly send to the network, eg. chat applications), photo editors, ...

Currently this is supported on Android but not on iOS, QCameraImageCapture::​isCaptureDestinationSupported(QCameraImageCapture::CaptureToBuffer) returns false on iOS. The only capture destination supported is QCameraImageCapture::CaptureToFile.