Generating a single pdf file makes maintenance easier than keeping track of the html page with image files. Acrobat should be used for scanning documents that cannot be processed by OCR, like chemistry documents. These documents are smaller and display better using pdf rather than a gif or jpeg. Another advantage is that Acrobat can compile these scanned pages into a single document. If pressed for time, conversion of a document to pdf is faster than HTML, but they may result in files larger than HTML equivalents.
Acrobat documents allow for cutting and pasting to other documents.
Format is preserved better than HTML, especially with Acrobat 4.0. Like HTML, Acrobat PDF files can implement forms, which a server-side program can use to take user information and generate an HTML or PDF reply page. Because PDF files contain higher-quality images and format, they can look and print better than their HTML equivalents. Acrobat 4.0 allows for in-line editing and annotating. This is useful for collaborative work.