In one of the intro lectures, the professor remarked that (paraphraaing here) 'now I am not naive--I know you will probably end up programming in Java or python when you reach the professional world, but the purpose of this course is not that you will actually go out and use racket in your life as a business programmer, but instead that your knowledge of racket will change the way you program in Java or Python'.
So there's really two types of learning--learning a language to use it, and learning a language as a sort of intellectual feast to bring back to your own.
This also has paralells in (human) language. The only languages I've studied are French and Hebrew. French has 'que' which can combine two noun phrases in a way that doesn't quite exist in English, and Hebrew has construct state.
[1] https://www.coursera.org/learn/programming-languages Sorry if I make a mistake here, Im not really very knowledgeable about either language, but I hope the general point stands.