There are several reasons why someone might choose to use Fidus Writer instead of Google Docs. Some of the key advantages of Fidus Writer over Google Docs include:

• Fidus Writer allows users to easily insert and edit mathematical equations, which is useful for scientific and technical documents, while Google Docs does not have this capability.
• Fidus Writer exports documents to a variety of formats, including PDF, EPUB, ODT, DOCX, LaTeX, and JATS XML, while Google Docs supports fewer export formats.
• Fidus Writer is customizable and extensible, allowing users to add or modify the functionality of the software by writing and contributing their own code, while Google Docs is a closed-source, proprietary product.
• Fidus Writer is built using web technologies, making it usable from computers with a web browser, while Google Docs is a cloud-based application that requires an internet connection to use.
• Fidus Writer is a semantic editor so that the output can be used for conversion to multiple output formats that are specific for publishing.
• Fidus Writer has more extensive citation features.

In summary, while both Fidus Writer and Google Docs are tools for creating and managing documents, they have some significant differences in terms of their features, accessibility, and customization options. Depending on an individual’s needs and preferences, they may find that Fidus Writer is a better fit for them than Google Docs.