With something like a garage door, knowing its state is very important, perhaps more important than knowing when the sensor has been triggered. When someone leaves the garage door open (kids), this is what we need to be notified about. Is the Notifon up to this task?

Also, range might be a real issue when the nodes are placed outside or in the letterbox.

One more thing, and this is just a personal preference in response to the idea that I "won't want to hide the device". I don't understand why people think white plastic is the best choice of color. So many cheap kitchen appliances are white plastic. If you have floorboards and warm living areas with warm tones everywhere, shiny white plastic objects are an eyesore. IMHO.