I think Rachio was making sure they worked out of the box. I ordered 1 Kit (wifi + single sprinkler) as well as 5 stand-alone. They sent me an email right before shipping saying that, although they believe one hub could support up to 8 devices, they are currently supporting only four for a positive user experience. So, I had one of the standalones upgraded to a kit. That was a preference, since I had half in the front yard and half in the back.
Yes, my controller is for the in-ground sprinklers, as well as a in-ground dripping system around the entire foundation (Texas black clay). I have 4-spout adapters on the water faucets in front and back, and I have an East and West device for the beds. The third on each hub has a hose attached without a schedule. It is much easier for my wife to click the button (for 10 minutes) than trying to open the value.