Good question and I will try to explain the situation as best I am able to.
History Lesson... Over on the ST Platform, a user created a SmartApp called InfluxDB Logger that could subscribe to all sorts of events from various devices, and as these events came in would be converted into an appropriate http call directly to a local server running InfluxDB.
Once Hubitat was launched, some users decided it would cool to port this smartapp to a Hubitat App. There was a version or two floating around the community, which eventually received some tweaks and updates and eventually landed in the Public Hubitat Community GitHub repository at GitHub - HubitatCommunity/InfluxDB-Logger. I was one of the people that enhanced the app by changing all synchronous http calls into Hubitat's (new at the time) asynchronous http calls. This was in response to the belief that this app was somewhat responsible for hub performance degradation over time. Since I had experienced this issue, and was using the app, I had a vested interest at the time.
Soon thereafter we saw the beginning of the interest in NodeRed as a means of monitoring the health of the hub and logging both Event and Live Log data via webSockets. It didn't take long for someone to use NodeRed to combine the Hubitat webSocket event data with InfluxDB. Since this removed the InfluxDB App from the Hubitat hub, and all of its http calls to InfluxDB, many found this to be an attractive solution to avoiding hub slowdowns (myself included.)
This is how NodeRed entered my home automation architecture. I have NodeRed, InfluxDB, and Grafana all hosted on an always on Windows 10 'Home Server'. This same system also runs a Plex Server, Channels DVR server, Ubiquiti Unifi Controller, file shares, backups, etc...
I have not moved any of my automations into Node Red. I only use it for monitoring the responsiveness of all three of my hubs, and for logging Hubitat InfluxDB data. The recent excitement for Node Red within the community has not intrigued me since my hubs are all running very smoothly.
Hopefully that helps. Things have changed since the early days of Hubitat, which is what makes this platform so interesting. We have amazing Hubitat developers as well as Community developers always coming up with new ways to accomplish things.