The one thing I could imagine doing with a blue-tooth enabled light would be operating it remotely.
I.e., if I'm not sure where my light is, but I can turn it on to beacon, like making my car-lights flash in a crowded parking garage.
But, oddly enough, I could not tell from what David C. said, whether he was going to make the lights blue-tooth operable or not. There was a lot about tracking, which I have no interest in, and nothing about making lights go off and on.
I don't really want a light with a tracking collar, if that's all it does. And the one he showed is far too big for key-chain duty, so it cannot be a tracking collar for my key-chain, either.
So I was a bit puzzled about all that.
But I like the 3-AA stubby!
ETA: And I really liked the CR123 version of the Preon 0, i.e the ultra-small, brushed stainless number with the magnet in the back. Very slick, and great for a set of keys. (Though I do wish that they'd move to three levels, i.e. one sub-lumen low around 0.5, a medium around 8-10, and a high of 150 or so). Still, great looking light, and a natural addition to the line.
And I'm at least intrigued by the idea of mounting that in a ball-joint as a head-light. Can't decide if I like it or not, but there's something to the idea.