> Anytime someone would ask him to make a pdf copy of a document he would print it out, scan it on the copier and email it to himself.
That's a pragmatic strategy to ensure that sensitive information isn't leaked.
Other than potentially including useful vector formats of artwork such as seals, logos and signatures, the visibility and/or mask settings can easily hide sensitive information that is trivial to extract later with standard vector editing software.
The print+scan method ensures that the person sharing the file is fully aware of exactly what is being handed over. It also deals with redactions which were not implemented properly.