The problem with most of the Lg G2 or the Moto X functionality is that they are meant to work with an additional motion/voice processor which is basically a very low power consuming core that is active at all times and governs such functionality.
The ascend p6 in house quad core cant be optimized for that.
Even if they are certain apps like that they would have a preaty hefty battery drain since they implement it by forcing the screen to be on at all times with 0% brightness and a massive full screen widget which will register taps.