Just using Node-RED since some months and building some flows for home automation.
For example: I am using some cast nodes (e.g. node-red-contrib-castv2) to send latest images from webcam to my Google Nest Hub via Chromecast.
Today I found https://cast.home-assistant.io/
A service that casts the Home Assistant Dashboard to any Chromecast device. The special "magic" is the support of the user interactions on touch devices like Google Nest Hub (no browser embedded in Google Things!). You can click on switches and sliders and the interaction is recognized. MAGIC!
Here you can find a video from Home Assistant:
Would it be possible to have it in Node-RED?
Probably, although not out-of-the-box. The home assistant casting tool is open source (https://github.com/home-assistant/home-assistant-polymer/blob/dev/cast/README.md) and can be forked/modified for Node-RED dashboards. However, as the setting up for home assistant instructions describe this isn’t for free as you’ve to set up licensing with google for your cast app.
You are right. It will cost $5 one-time fee for Google Cast Developer Console.
I would pay the $5 right away if someone would build a viable solution. The app can then basically be used by anyone.
It will work, to a point... but it wasn't really that nice so I abandoned it.