Synthetic speech, noted earlier, is an option that some organizations may wish to consider for publications such as magazines, television guides, newspapers, etc. Documents and materials which will be used in part to glean information are well suited to this.
Other applications to consider for synthetic speech rendering are indices, bibliographies and notes which are often present in works of non-fiction. It can be much faster and far less expensive to produce a source file of an index and render synthetic speech from it, than to produce it with human narration.
Note that a source file is required for the above applications. Other factors such as quality of speech synthesizing program/system and complexity of vocabulary and/or multiple languages in the source document should be given consideration in determining if this is a viable option.