That disk compression is a good one. I tested is and saved 7.5GB of space.
I kid you not when I say I know people who would regularly print things on paper, then use the photocopier to scan them to network drives as PDF's. Afterwards they would just put the paper through the shredder. In all fairness to them though, it was the quickest way to do it as a photocopier with a document feeder is incredibly quick at scanning and it wasn't exactly their fault that their computers didn't have the ability to print directly to PDF or TIFF from the software they were using. Also getting an IT department to install any third-party software on company machines is a nightmare, if not pretty much impossible.
Microsoft's XPS solution wasn't really feasible due to having low adoption, little recognition and uncertain future compatibility, which isn't such a problem with PDF, TIFF and JPEG, and they're widely accepted long term archival formats.