Using printed documents clearly have important drawbacks. They are produced from murdered trees (so more papers about global warming are printed), are difficult to search (maybe except several books with useful indices) and occupy physical space. Also, printed medium encourages writing useless texts. However, they still cannot be replaced by electronic documents.
PDF and similar file formats represent pages exactly as printed. But they represent whole documents differently than a sequence of pages. Operations like merging several documents into one or dividing one into several with some pages are trivial with printed documents, but commonly used software does not support them (except for printing some pages).
Documents are not the only structure causing problems unknown in printed media – pages also lead to difficulties. For books small pages with text are put on larger pages to be printed, binded and cut. Therefore, a document has both logical and physical pages, which are different in large documents (reading a two column article on a screen where only a part of page’s height is visible looks similar to this problem). Also, at least some software for merging logical pages into a physical one tries to render documents in device-dependent ways – making the document unsuitable for viewing on screen, printing, or both.
Another problem with physical pages of many logical pages is that the user may prefer other combinations. For example, a document with two A4 pages on one physical page is not suitable for users with printers supporting only A4 (if the document contains text, it will be much smaller then expected). Of course, even with a single page there are problems with page scaling. Americans use Letter paper while Europeans use A4. Software assumes a mix of these formats which will scale pages and add useless whitespace (or crop out some text). A common, but not too harmful, sign of such problems in uneven margin (A4 and Letter have different widths).
The problems with page formats may be solved in two ways – providing the document printed on appropriate paper, or providing PDFs in both formats. Clearly, the second way requires formatting independent of page format, impossible with WYSIWYG software.
There are cases of documents printed, corrected and photocopied for publication (or printed again with new information on the same page). This work could be completely automated with PDFs edited in a programmable way, e.g. using pdfTeX. But this would require changes in the habits of users which could be better spend to avoid using printable documents, since hypertext is better and does not have these problems.
