Most hubs require instant updates (think dashboards or chat). Standard HTTP requests won't cut it because the server can't "talk" to the client unless asked.
Build a mechanism where the hub attempts to re-send failed requests 3 times before giving up. How To Make A Serverside Hub Part 2/2
Building a server-side hub is about moving from "direct communication" to "orchestrated communication." By centralizing your logic, you make your entire ecosystem easier to monitor, secure, and scale. Most hubs require instant updates (think dashboards or chat)