Well, that and every time you touch a DOC/DOCX file it reformats itself to your local settings, fucking up the entire layout. PDF is a terrible, inefficient, poorly (or at least variably) implemented format which was proprietary for two decades but is now about the best option we have for a document to look the same at the recipient end as the sender and still include text, vector, bitmapped, semi-interactive, and certifiable/traceable contents.