When they introduced the Sacajawea dollar coins, IIRC people started hoarding them because they were 'different.' For some reason people though that if they held on to them they would be 'worth something some day' which is a useless thing to think when everyone is collecting them. I think that the fact that they were gold colored didn't help either. People (even if only on some subconscious level) didn't view them as money.