Remote Analytics cluster documentation

We don't seem to have any documentation explaining the process of setting up an "Analytics only" cluster, along the lines of

• Why would you want to do this.
• What are the requirements for the cluster.  (A least a minimal Data service running, etc.)
• What are best practices for performance, HA, etc.

We do have documentation on how to set up remote links here https://docs.couchbase.com/server/current/analytics/manage-links.html but no indication of why you would even want to.