Because philosophy is such a broad field, you can put a concentration in philosophy to a very wide range of uses. Some majors go on to do graduate work in philosophy, with a view to teaching philosophy in a college or university. But more go on to other careers: in law, public service, journalism, business, computer science, medicine, religion and the arts. There is strong statistical evidence that philosophy majors do very well on the admissions tests required for graduate work in other areas.
The study of philosophy helps its students to develop their ability to analyze and clarify ideas, to think logically, and to present their ideas and arguments effectively, both orally and in writing. Because philosophers have historically focused on the most difficult and abstract questions, they have cultivated a standard of expository clarity and rigor rarely stressed so emphatically elsewhere. These abilities are useful in many occupations. Moreover, the development in recent years of the study of ethics in medicine, business, law, and environmental studies, has encouraged the use of philosophy as a preparation for these enterprises. It makes sense to study philosophy for many professional reasons, not only to learn to teach it to the next generation.
Philosophy can also be a way of inquiring into the concepts and methods of other disciplines you might be interested in, such as physics or anthropology or religion or the arts. Thus the concentration or a minor can be used as an adjunct to other studies. They can also be used by someone who is inclined not to become too specialized, as a way of investigating a wide variety of topics while at the same time pursuing a concentration.
Many of these advantages can, of course, be gained without concentrating in philosophy, by taking a minor, or simply by taking a number of courses in it.