Other than iMore friends, I don't know anyone who has purchased even one. Most I asked were not even aware they existed. And when I said they were $29 each, they all said "Nope". A few just laughed. I'm sure they'll sell millions of them. But, apparently, not to my friends and family. I might get one, if they were thin enough for a wallet. Otherwise, I don't have a need for one, especially not at $29.
Best quote in the article: "Granted, maybe the iMore audience skews towards those who would intend to buy pretty much anything with an Apple logo on it".