What's scary is Hue bulbs are some of the MORE performant of the IoT stuff I have - and work when offline.

That second part is the key - so much stuff is designed "cloud first" and that introduces lots of delays and errors when the Internet isn't working perfectly.

Yup, If you are prepared to crank out some JSON to your Hue hub, you can 100% control them offline. I do this via scripts for my Hue based outside lights. My Hue Hub is blocked from accessing the internet too.

Or simply deny to work without an internet connection, like Chromecast, even though you just want to stream local content when your internet is down.