The world of liquid-cooling electronic devices is typically reserved for high end gaming desktops and supercomputers running insane clocks speeds and voltages to maximise the performance of the hardware. The extra heat generated as a result of hardware being pushed to its limits leads to increased thermal output that require the thermal properties of liquids to cool the components sufficiently. Despite ARM designed processors and smartphones generally being lower power than their desktop counterparts, NEC who have been known to embrace some moonshot ideas in the past has decided that a smartphone requires liquid-cooling as well.
The Medias X 06E is a phone that is marketed towards women; incase the bright hot pink picture of a phone didn't give it away. Unfortunately the phone doesn't contain any glowing UV tubes filled with liquid being pumped into a massive radiator cooled by an array of LED fans; instead the phone utilises a water-filled heatpipe that draws heat away from the processor to a special graphite 'radiator' or heatsink where it can then be cooled more efficiently as you can see in the diagrams below. The processor that NEC decided required such out-of-the-box thinking was the Qualcomm Snapdragon 600, which has found its home in other devices such as the Galaxy S4 and HTC One, none of which have liquid-cooling. This processor is partnered up with a 4.7 inch 720p AMOLED display, 13.1 megapixel camera, 4G LTE and Android 4.2 out of the box, so despite the gimmicks there is a solid phone under that charade.
As for the reasons of including liquid-cooling and whether or not we'll be seeing it more often the future is an odd question. The design obviously takes up space in an already crammed smartphone interior and the extra weight wouldn't be helping it. The design does help keep the processor cool by moving the heat away from the CPU and increasing the surface area used for cooling, and I'm sure many of you are aware that phones can get warm when they are under load, such as gaming especially around the CPU area. The concentrated heat can caused temperatures to exceed the thermal threshold the CPU causing it to underclock itself inorder to preserve itself, causing a loss in performance. This was actually an issue that was prevalent in the LG Nexus 4, where it scored relatively low for a Snapdragon S4 device because Google was relatively conservative when it came to the thermal threshold. So in niche circumstances there is a practical reason for having it, but as chips get smaller and more efficient they won't require as much cooling, so realistically outside of the marketing department there isn't much reason for having it in future devices.
At the end of the day, this is the world's first liquid-cooled smartphone and it will be released by Japan's NTT Docomo sometime in June.