Correct, it is Bluetooth only (hence the long battery life), but it uses cloud-based tracking. Everyone with a smartphone who is running the Tile app provides the geolocation. If you need to locate your Tile, the Tile network will try to ping it. If anyone comes within 50 yards or so, their smartphone will forward the location to your phone.
It works best in an urban or suburban environment, where lots of smartphone users running the Tile app are scattered around the area. And once you are nearby, you can make the Tile Pro “chirp” to zero in on it.
It is not as foolproof as a dedicated GPS tracker, but it is cheap, and only requires a new battery about once a year. I have one hidden in each of my cars. It is a cheap theft recovery device that is certainly better than nothing at all.