There are also “coils” that vibrate to create vapour which happens at room temperature.
I also wonder whether it's more efficient in terms of battery use.
Ultrasonic atomization. It's used widely in manufacturing for applying thin-film coatings, because it provides a very consistent and controllable spray of very fine droplets. The technology has been applied to vaping by Usonicig, but it's not hugely popular - most people prefer warm vapour.