Just my personal opinion, but you couldn't pay me to trust Google with my automation system functionality.
We all know they like to add and then cancel software at a drop of a hat. Imagine spending a lot of time, energy and money into the Google ecosystem only to have it dropped in a couple of years. Now I realize that risk is there with any company, but I feel like with Google's track record, the risk is much higher.
I also don't want to give Google that much more data on me in general. It's terrible that amount of stuff they already know about me, I certainly don't want to hook up an entire house full of "smart" devices to the Google servers too.