Nixie Tubes have a special mode that is only used when placed on a train signal. However, it would be useful to be able to access this mode or a similar one, where it can display either on or off on each tube depending on if there is a redstone signal or display input incoming, and this mode could be toggled by for example right-clicking them with a wrench. There is a lot of functionality that this could add and wouldn’t require much work to implement.

#3311 is about the same idea, but has an example of how it could be implemented

It's not quite the same idea, although close enough, but my method of implementing it is different. Using a wrench on the nixie tube as I mentioned as a way to use this mode would make it so the tube would display the white light, and then when receiving any signal from redstone or a display link would make it turn red.