Nuclear physics and non-Euclidean geometry can justify their usefulness through results. The fact that only a few people understand them does not prevent their usefulness.
The usefulness of Continental Philosophy could consist in insight into moral, political, and social problems, but providing insight to a few specialists is not much use in those fields, especially not in democratic societies. Looking back on the history of moral and social change in the United States, I don't see such philosophies playing a major role. The thinkers who have made a difference have written for a general audience and in a much more accessible style. (Karl Marx and Das Kapital would seem to be an exception, but he and his evangelists wrote plenty of accessible interpretations of his ideas. The Communist Manifesto, for example, is a brief, readable, and rousing document.) If Continental Philosophers want to justify their existence, they should point to some benefit that their work enables, instead of just complaining that nobody understands it.
The usefulness of Continental Philosophy could consist in insight into moral, political, and social problems, but providing insight to a few specialists is not much use in those fields, especially not in democratic societies. Looking back on the history of moral and social change in the United States, I don't see such philosophies playing a major role. The thinkers who have made a difference have written for a general audience and in a much more accessible style. (Karl Marx and Das Kapital would seem to be an exception, but he and his evangelists wrote plenty of accessible interpretations of his ideas. The Communist Manifesto, for example, is a brief, readable, and rousing document.) If Continental Philosophers want to justify their existence, they should point to some benefit that their work enables, instead of just complaining that nobody understands it.