So a problem just came up today that encapsulates why IP addresses are still useful.
I have a webservice at http://jeopardy.local:9981, but typing that into a web browser gives "Server Not Found".
But if I type in http://<ipaddress>:9981 it works perfectly.
It turns out that the problem is that flatpak Web browsers can't resolve mdns names.
The world is full of stuff like this which unfortunately makes ip addresses the most reliable way to reach selfhosted services.