Coins have been offered at some recent Merchandise Special Events, and have remain unsold months later. The Character of the Month coins offered last year were used as Gifts with Purchase at the park's Disneyana and Disney Gallery shops. It seems that the park really wants coin collecting to take off, but customers are not hopping on the trend. I think there are several issues. Pins and Bean Bag Plush have actual uses, where coins and medallions really don't.
Price is another concern.
There are individual pins that sell for a hundred dollars or more at auction. These coins, not being Limited Edition or otherwise unique, don't have the same individual value. Once the Dated Pin is retired, an entire set that contains this coin might have collectible value. But the collectors don't really seem interested. If people are not buying them as collectibles, perhaps they will buy them as souvenirs.