This feature should must be use Gyro, Accelerometer and Barometer.
And here is the compatible list.
iPhone 6S - 3-Axis gyro, Accelerometer, Barometer --PASSED
iPhone 6S Plus - 3-Axis gyro, Accelerometer, Barometer --PASSED
iPhone 6 - 3-Axis gyro, Accelerometer, Barometer --PASSED
iPhone 6 Plus - 3-Axis gyro, Accelerometer, Barometer --PASSED
iPhone SE - 3-Axis gyro, Accelerometer --FAILED
iPhone 5S - 3-Axis gyro, Accelerometer --FAILED
iPhone 5 - 3-Axis gyro, Accelerometer --FAILED
Apple should must be add this iPhone 6 or later. There is a hardware inside for it. And it helps to Apple reduce Sleep/Wake button and Home button/Touch-id service costs.
Edit:
I watched this video.
0:47 - 0:52
Looks like there is no need barometer for it. And all m7 and m8 models can handle this feature. So its a developer beta1. Must be added in later beta's. I think Apple working on it background for getting all models. Maybe Apple added this feature 6S only for demo. Its a simple and great software innovation. And ofcourse its a Win-Win. Apple wins: Reduce button service costs. Users wins: Easier life. Better than double touch home button to wake.