It is recessed in the crown of the light, right? Lots of LED lights are designed like that, no worries. LEDs are TOUGH.

As for why this design, not a Photon, for me it is simple: harder to turn on accidentally. If I have a light that will throw light for X duration, I want to know that it isn't going to get shorted by Y just because I had it in my pocket. Yes, it is a new kind of battery, but they are small and inexpensive if you know where to look. And it is physically a lot more robust than the coin light.