Because isn't this just "WordPress 2 Markdown".
Unless I'm mistaken, this does not recreate your WordPress theme/template to be used in Hugo (nor nothing specific to Hugo).
It's just exporting your blog posts from WordPress database into a Markdown file format.
Note: still very useful, I just find the name confusing.
It does put your files into a Hugo directory structure and includes the smol theme. It doesn't recreate your theme, plugins, or process your images, but I also have tried to be very explicit that it just converts your pages and posts and is the starting point for a conversion.
When you put an export file through it, you'll end up on this page: https://imgur.com/a/UUMB6ve where you can download a zip or tgz of the site and you'll clearly understand what you're getting before you can choose if you want to have the remaining pages/posts converted.