From my experience in industry, while hardly any programmer will ever need to write a modern code generator, few things are more useful in practise than being able quickly to design a suitable DSL and implement a corresponding performant and correct lexer and parser. This is not something that can easily be picked up on the side.

In addition, understanding what happens under-the-hood when you program in a high-level language is an eye-opening experience for many students. This sentiment comes up in student evaluations year-in, year-out.