As far as I can tell without actually reverse engineering it and going deep, the Vizio app is just a Chromecast app. It’s different from all the other TV manufacturers that have protocols with apps that send common commands like “power on” or “input HDMI 2”.
Chromecast instead handles things like “play this stream”, and it has a sidechannel to specify volume.
Our Chromecast support is undergoing a major update in 5.0. I think it’s pretty likely it would at least power on the Vizio TV, but this has not been tested. It does work for all kinds of other Chromecast devices like NVIDIA Shield. We would be happy to add a few beta testers if you contact support on that topic to try it.