goodphoto.kr shows us the new Sony a5100 in action. The rear lcd touch screen is used to activate autofocus and trigger the shutter simultaneously. This can be useful when the camera is not held in the standard position and the shutter button is at an awkward position to depress. This is not possible with the sony a6000. The chart below is a quick comparison between the Sony a5100 and the a6000.
Watch the a5100 touch shutter in action in the video below from goodphoto.kr.