Muse meditation headbands

Anyone here used Muse or similar “neuro-feedback” devices to help you meditate/relax/sleep? How was your experience? Did it work for you? I am little puzzled. The device says it transmits aural feedback with data extracted from your brainwaves: choppy mood, stormy weather sounds, calm mood, pleasant weather sounds. But I don’t need a device to let me know how calm or agitated my mind is. How is this feedback likely to be of any use to a meditator?

It comes bundled with a lot of sounds, so that utility is there, but the claim the feedback actually helps sounds sketchy. And it costs $250. That’s a lot of money for a bunch of sounds.