> There are many cases images are exported as PDFs.

One client of a client would print out her documents, then "scan" them with an Android app (actually just a photograph wrapped in a PDF). She was taught that this application is the way to create PDF files, and would staunchly not be retrained. She came up with this print-then-photograph after being told not to photograph the computer monitor - that's the furthest retraining she was able to absorb.

Be there no mistake, this woman was extremely successful at her field. Successful enough to be a client of my client. But she was taught that PDF equals that specific app, and wasn't going to change her workflow to accommodate others.