alt Hacker NewsWell so I glanced at what that project does.
Congratulations, you've managed to "compress" PDF files by rasterizing every page to JPEG, while destroying all the vector and textual information in it.
The resulting PDF is nothing like the input -- it's just a bunch of blurry JPEG images wrapped in a PDF format.
You can't search or copy the text, and trying to print it will just make a blurry mess of the text.
Nail it. I requested a 50% compression for a 200MB PDF file that contained pictures, and the tool made it an illegible mess. I can't imagine using this tool for anything serious, like tax returns, that requires a machine-readable file.