“I once wrote an essay laying out four reasons for its enormous success,” Gitelman said. “First, PDFs offer page images – like facsimiles, like xeroxes, like microfilm, unlike word processing files or most proprietary eBook formats. This means they feel stable. They retain layout as well as content. Second, as page images, they are handy in publication workflows. Every book, every analog publication, has been a PDF somewhere in its life history. Third, they are easily transmissible across digital networks, even in low-bandwidth environments.”
Article source: https://www.huffingtonpost.co.uk/entry/what-pdf-stands-for_uk_6a6b4283e4b01948ae9a31c1