The fraud aspect doomed Coin (and probably the similar competitors) from the start, IMO. It either wouldn't catch on (in part due to fraud or fear of fraud). If it did take off initially, we'd enter a carders' utopia where fraud would be easy because merchants would swipe any magstriped gadget without blinking, which would kill Coin when the card networks clamped down. And regardless, it basically only works in the US, where the clock is ticking towards the death of magstripes -- though I guess if they sell tens of thousands of magstripe Coins before that happens, they don't care.
It may be useful for loyalty cards, but even that has similar problems with the cashier being confused/skeptical, or just the hassle of talking about it when you just want to finish your transaction and leave. Apple Pay has apparently opened the way for loyalty cards over NFC[1], so hopefully that will keep spreading both in merchant numbers and availability on other mobile platforms.
[1] http://9to5mac.com/2015/06/10/verifone-apple-pay-loyalty-car...
