Because no one manufacturer does everything. In my home, I have... Nest alarm, Lifx bulbs, Onkyo speakers, WeMo plugs, Meross adapters, Alexa voice controls, T

Because no one manufacturer does everything. In my home, I have... Nest alarm, Lifx bulbs, Onkyo speakers, WeMo plugs, Meross adapters, Alexa voice controls, Toshiba TVs, and a bunch of no-name Chinese kit. And none of those manufacturers talk to the same standard. So I end up using IFTT and I've cobbled together controls out of various open and closed source code to make them work together.