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

• Fidus Writer is free and open-source, while Adobe InDesign is a commercial product that requires a paid subscription or one-time purchase.
• Fidus Writer is built using web technologies, making it accessible from any device with a web browser, while Adobe InDesign is a desktop application that is only available for Windows and macOS.
• Fidus Writer offers real-time collaboration, allowing multiple users to edit a document simultaneously, while Adobe InDesign does not have this capability.
• Fidus Writer allows users to easily insert and edit mathematical equations, which is useful for scientific and technical documents, while Adobe InDesign does not have this capability.
• 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 Adobe InDesign is a closed-source, proprietary product.

In summary, while both Fidus Writer and Adobe InDesign 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 Adobe InDesign.