Recording the narrator talking into a webcam is an easy way to make our video more engaging. But we should use this technique sparingly.
Showing the narrator is a good way to introduce a video, but we may not want to display the narrator throughout.
Viewers naturally relate to a voice-over when they know how the speaker looks like, but it can be distracting to see the narrator's face from start to finish. A good compromise is to use the webcam to introduce the video (perhaps using Picture-In-Picture), and then fade it out so that the viewer can focus on the content.
Camtasia can capture video of the presenter and the screen at the same time, but we'd never recommend this for a professional ...