It prevents OneAgent traffic be processed and stored by that node. It can be used either for a temporarily forsake this node (e.g. before removal) or lowering the node CPU utilization and spend it for instance for retrieving the data for reports.
With that option you can make the node no longer process OneAgent data. A use case is that the node can be used exclusively for WebUI usage. This allows for higher stability, better cache behavior, and faster UI response times as it no longer requires processing power for processing OneAgent data.