As a teacher, I have learned more about this fellow in 20 seconds of looking at images than I can learn from reading his essay.
The video is stable (probably shot on a tripod), so I know that the teenager thinks ahead and he's careful with details.
He appears to like the outdoors and he has a positive attitude. Yes, I can pick up his optimism in his essay, but I have to admit that I already knew that he is a confident, upbeat person just by looking at his photo.
That's the power of a portfolio. In three images, the student has built a profile of himself in the mind of the viewer.