Add other devices that can use the hub and app
Of course you can think of lights and alike, but there would be many, many competitors. Adding a smart smoke and heat detector, would be beneficial. This is not a complicated device, the majority of the technology is already designed by tado and, well, a smoke detector ain't something complicated. Same hub could be used for the thermostate and radiator thingies. It could have a similar design as the thermostate. Changing the app might take some time.