When my students and I engage in dialogue, my own understanding and insight increase. Plato's Cave Allegory helps students realize that education depends upon distinguishing illusion from reality, thus enhancing the freedom to choose, even if one only chooses the Socratic wisdom of not pretending to know what one does not know. Increased autonomy leads to increased dignity. When I dwell among autonomous, dignified human beings, my own autonomy and dignity are also enhanced. This is especially important for those of us who believe in democracy as the best form of government.
Democracy dies without the autonomy and dignity of citizens.
To say that dialogue is universal means that it fosters a kind of education that promotes common benefits open to all. This is not true of all forms of education. If a person learns how to confront an opponent by killing or maiming more efficiently through the martial arts, that kind of education is unlikely to provide mutual benefit. We might draw an analogy with the principle of nuclear deterrents and argue that if everyone were to learn a martial art it might discourage others from attacking us. However, in the case of individual safety, differing levels of skill would probably encourage rather than discourage those who seek to display their prowess.