What I learnt from the project was that the most important part was the model bus. This made it acceptable for my SO to have the thing in the house and she's the one that uses it a lot more than me.
I've built other "IoT" things around the house (lots of Amazon Dash buttons that don't do what they were intended for and other stuff) and the packaging matters a lot. It makes the things seem less like technology and more like part of the environment.
Since I wrote that blog post TfL have created a proper API and it has loads of goodies in it: https://api.tfl.gov.uk/
It seems that people like things by how useful they are for them, not by how cool they were to build, which is frustrating but not surprising.
The packaging is why I got a 3D printer and am learning CAD. I want to create little stylish boxes for my sensors, so they look more like devices and less like bombs.
Come to think of it, I should have added an SMD switch to it, maybe I'll make a new one with a 3d-printable case. That's an idea...
If you have temperature/motion/light/etc sensors around the house, you could use those, or maybe show the HomeAssistant dashboard on it.
I start asking myself what are the status indicators we really need? That people would pay $50 for?
Guess this is a pretty common need! My take based on a priority sign: https://github.com/Seed-Up/BusSign
Braggart. Fat lot of good it did you, until the Italians came up with batteries.