A few reasons, although you are only seeing part of the picture with the project. The lectures were all theory-based (more along what you would find in the book).

1. I had a whopping three weeks to prepare this course from scratch (welcome to Uni teaching) and it was what I could scrape together in that time.

2. Parsing is highly useful, and I felt my students could benefit from it.

3. It was what I did in undergrad.

4. It was not too difficult to accomplish, and a project like this can easily get out of hand for a semester project.