They are very easy to update . The same document can be viewed by everyone simultaneously. With hypertext links, any see references are very easy to find. Images are very easy to make. Readers often don't know if they are looking at the latest information.
More examples increase the bulk of the documentation, which makes it more imposing .
Referring to related documentation can be bothersome, so there is a certain amount of duplication of information which is covered more fully in other places. When this information changes, it can be very complex to change it everywhere. To find a specific answer to a specific question , the only way to find the information is to memorize where the answer may be in the documentation, ask someone else, or as a last resort, search through everything. There is not much space available on a single computer screen as compared with a piece of paper. Scanning a long file by scrolling down a computer screen can be confusing.