The eagle is rendered sharply while the vines in the background are out of focus. The viewer's attention is drawn to the eagle rather than to the surroundings. An even larger aperture would have further blurred the background. On the other hand, in landscape photography it is common to render the entire scene sharply. For this type of effect a small aperture would be used.
Much ado is made of the comparative quality of primes versus zooms and so on.
My personal perspective on the issue is that you might have the world's sharpest set of prime lenses but they do you a fat lot of good sitting in you camera bag at home or in the car. A zoom allows you to increase the odds that you will have the right focal length on hand when you need it. One advantage that primes tend to have over zooms is that they are 'faster'. In photo parlance this means that they have larger maximum apertures. As a result it is possible to use faster shutter speeds than is possible with zooms.