No, a SIM enabled Apple watch sounds like an expensive solution to an already solved problem in this case. Apart from being virtually free the Android-based solution also stands out for being open versus the closed nature of the Apple watch. I use (other instances of) the same device as remote-controlled media player (a Defy running MPD connected to a car stereo in a large-ish wooden rectangular box with beefy speakers, a battery and several power hookups and charging ports (including 20W of solar panels to keep the thing going when there's light to be had)) or a trailer camera (a screen-less Defy in a custom wood+aluminium enclosure mounted in the front of my wife's horse trailer, the thing creates its own "cloud" through its Wifi adapter so she can see her nags on the road, it powers up and down based on the trailer hookup being powered with the battery as backup) and other similar contraptions.