HomeKit appears to be a simple start but still has enough configurability to grow.
You basically group your home into parts starting with the entire home, rooms and Zones This way Siri can
easily understand a command like "Turn off all lights downstairs".
All this is kept in a database so each device will not need to be reprogrammed and is easily editable. I suspect that HomeKit will
grow as the market in general grows but it should be easy to get off...