Some people believe they have healing properties, but I haven't noticed. I just enjoy the calming warm light it emits. Minerals do release radiation, but in such small amounts that it shouldnt actually be producing health benefits, but it can't hurt?
They release negative ions. That helps purify the air, improve mood and/or sleep, and also helps counteract the positive ions constantly release via electronics (cell phones, wifi, etc.) I leave mine on all the time and REALLY love it!
I am by no means an expert but they are supposed to be able to help clean the air with their ions. They help with issues cause by electronic devices, bacteria, and even mold. It is also said that they can increase oxygen levels or rather the flow of oxygen to the brain which can increase alertness & energy. Plus, they give off a romantic light and look pretty cool in a bathroom or kitchen.