When you add a battery and a wireless radio, you add a lot of thermal mass and weight. If you attach this directly to the sensor (the way several of these other clamps are doing), you end up with inaccurate and slow measurements. We did consider this, and worked on it for some time, but the reality of physics got in the way.
Our goal was to make a fast-response, accurate, and repeatable temperature sensor... and due to the physics involved, it was necessary to remove all the mass and weight from the sensor itself. I hate wires, too, but I'm not sure I could ask you to pay an extra $500 (a piece!!!) just to get all of this accuracy and fast response in a tiny sensor without added mass.