If you haven't see one already, check out the Grandstream GXV3275. It's a 1024x600 touchscreen VOIP telephone, running Android.
The v6.0.2 Home+ app works on it. But during setup it requires WiFi be turned on. Which the phone does possess, but it also has a wired Ethernet connection. If WiFi isn't on then the setup portion won't find the main repeater. I turned it on and it recognized the existing system. It remembered the system such that it came up again just fine with only wired ethernet connected.
As Android pushes out on to more devices like this it'd be good to have the software look for an IP connection, not necessarily just a WiFi one..
But don't feel bad, plenty of other apps make this mistake too.
Also, when is the Android app going to get feature parity with the iOS version? As in, whole house?