The area information could be used for many things, but a specific use case is to turn on or on or off all lights in an area, e.g. outdoors or kitchen with one node (which dynamically represents all lights in that area).
The Node Red integration is developed outside Home Assistant. Post an issue here https://github.com/zachowj/node-red-contrib-home-assistant-websocket
PS there seems to be at least one example in the cookbook of using areas https://github.com/zachowj/node-red-contrib-home-assistant-websocket/tree/dev/examples/cookbook
Because Node-RED hasn’t implemented it.
There is not much the Home Assistant project can do about that.