I guess you dont want to ever send an SMS then as well as anything you send to something other than iOS is going to hit google servers.I guess this is good as long as my messages never touch Google servers. If they do … sorry Apple you screwed up. I cannot see a single advantage of this over iMessages. Google must have paid some pretty money or their lobbyist paid a lot to some eurocrats and hinted Apple might be forced.
Also assume you dont want to use Apple products as Apple is a pretty big user of Google Cloud services.