This is the kind of thing that I think could be really amazing, or a total dud. I'd definitely need to be able to try it out before I throw down over a hundred dollars.
Another co-founder here-- definitely understand the skepticism. If you'd like to learn more about the science behind Moment, check out this page: https://wearmoment.com/learn
One of the co-founders of this company, just to be transparent about that, but the vibrations are definitely precise enough to create distinguishable shapes and patterns on the skin.
We're using linear resonant actuators, rather than the ERMs normally found in wearable devices and personal electronics, because they allow us to have precise control over the intensity of the vibration we're creating. We take advantage of this and the psychological phenomenon of tactile illusions in order to create the sensation of vibrations that actually move from one place to another on the surface of your skin--allowing us to convey an upcoming turn or the passage of time just through your sense of touch.