Ever since the original Moto RAZR V3 came out 10 years ago, the smartphone industry has had a strange obsession with skinny phones. Not because shaving a millimeter or two off a device will give it more functionality, but because it's an effective marketing tactic. In emerging markets in particular, slimmer phones at slimmer prices enjoy a distinct advantage. Gionee, a handset maker based in China, isn't very well known, but it's looking to make a name for itself with devices like the $375 Elife S5.5. At 5.55mm thick, this svelte beauty currently claims the title for the thinnest smartphone on the market. To put that in perspective, that's a full two millimeters skinnier than the iPhone 5s. I spent a few days with the device to see if thinner really is better.