rightwriter,
I have a relative who gave some of my kids $2 bills as a gift, and I brought them to a CVS to pick out toys to buy with the gift money. The cashier refused to accept the bills, saying “that’s not real money”, so I ended up paying for the toys using my card. Those bills are still floating around the house somewhere.
As for the dollar coins, I think the two main uses for them are for machines that have to give large amounts of change such as ticket machines for commuter rail, and gambling.