Federated applications face several challenges to mass adoption, including a steep learning curve and a lack of user intuitiveness. Users must understand that federation involves not just one server, but many different servers that can read content from each other. This poses a problem for search engine optimization, as multiple instances hosting the exact same content can lead to low SEO ranking. Additionally, authentication is an issue, as users’ account logins are usually locked into a specific instance, making smaller instances less attractive. One potential solution may be a centralized login server, though this could introduce its own set of issues.
https://plug-world.com/posts/the-federated-app-problem/