No Network Access
Sandboxes don't have network access, so if a malicious document can compromise one, it can't phone home
Dangerzone can optionally OCR the safe PDFs it creates, so it will have a text layer again
Reduced File Size
Dangerzone compresses the safe PDF to reduce file size
Open Docs Safely
After converting, dangerzone lets you open the safe PDF in the PDF viewer of your choice, which allows you to open PDFs and office docs in dangerzone by default so you never accidentally open a dangerous document
Dangerzone works like this: You give it a document that you don't know if you can trust (for example, an email attachment). Inside of a sandbox, dangerzone converts the document to a PDF (if it isn't already one), and then converts the PDF into raw pixel data: a huge list of of RGB color values for each page. Then, in a separate sandbox, dangerzone takes this pixel data and converts it back into a PDF.
Read the blog post for more information.