It is used in high tech applications, such as medical lighting. PerkinElmer's Cermax is one such example. It is a lot more expensive than metal halide, and there is not really a justification for the xenon in reef application unless you happened to find one really cheap from a liquidation shop that sells used industrial equipment, and has no other use for it.
There is a large range of wattage and spectral output, but most of them put out 5% UV, 50%IR, and 45% visible. There is a major peak near the high 400nm range, so the color is not that bad for reef.
There are a few application in high end automotive, and they can be fine for smaller setups. But again, there are MH for that, and no real advantage that I can see with Xenon.
Note that I am talking about Xenon discharge lamp (HID), not the incandescent bulb (tungsten wire one like this :arrow: :idea: ) that is filled with Xenon gas that you can get for a few bucks per bulb.