Zoom and prime lenses both have their own purposes and respective pros and cons, although beginners typically default to using zooms, particularly since most kit lenses are of that variety. There are a few properties than should make you consider grabbing a prime lens instead, however, and this excellent video discusses one of the subtler reasons using one can benefit your photography.
Coming to you from James Popsys, this awesome video discusses the benefit of using a prime and how it forces you to be more deliberate and develop your compositional eye. Advocates of prime lenses will often say that you can "zoom with your feet," but this is a bit misleading, as different focal lengths will produce different perspectives, even if you adjust your position so that the subject is the same size in the frame. Rather, a prime lens removes the convenience of a zoom, which allows you to stand in one spot and create several different compositions. In doing this and thereby forcing you to move throughout the scene, you will be forced to put more thought into your compositions, and you might find a shot you would not have been aware of otherwise. Check out the video above for the full rundown from Popsys.
As a street photographer I always use a prime lens and one particular reason is size and weight. Personally I’ve never got on with zooms, usually sticking to one focal length anyway. I like the restriction of one focal length and I feel discovering what those restrictions are with my lens has helped me to a better understanding of composition, depth of field and getting the most from that one lens, without, for me, the distraction of a number of different focal lengths (or a big weighty lens). I’ve seen enough articles/videos now stating the case for either primes or zooms to know we are all individual and, between the two types, whatever lens people choose, there really isn’t such a thing as a completely bad choice. We photographers really are spoilt for choice that we can all own any particular combination of equipment that only needs to feel right and make sense for yourself.
I understand the intention of James's video. But using a zoom thoughtfully is just as good. Simply learn that the decision for a specific focal length is as important as other decisions, like the aperture or shutter speed. For me, the restrictions of a prime are only bearable, because it is usually on a higher level, offers wider apertures and is lighter. The fact that it restricts us is not among the benefits of a prime for me.
I use both primes and zooms regularly. They're different tools for different use cases. With either one, the point is to compose intentionally, instead of just shooting from whatever spot you happen to be standing.
Though sometimes due to external limitations you are restricted to one spot, or at least a limited area, such as the media pit at a large public event. When you don't know before you get there how far from the subject you're going to be limited to standing (or kneeling) zooms come in very handy.