Deploying your Factory using FoF allows you to easily make your Factory and the model contract available to other developers/projects by creating a shared codebase. Also using FoF introduces the possibility of inserting two possible fee-based business models in your Factory:
1) Creation fee. It's a fixed fee that a user must pay when cloning the model contract from the Factory.
2) Usage fee. It's a fixed or percentage fee that users must pay when using the cloned model contracts from the Factory.