Now, I love dollar coins, really. I used to think the big old Ike dollars were keen when I was a kid, and I still keep a couple just because. But I acknowledge that the big Ike's were not so pocket friendly. The Susan B. Anthony dollar coin - well, I thought that was a cluster fuck. It was almost the same size as the quarter, and the same color. Coins should be different sizes and/or different colors. If you can't pull a handful of change out of your pocket/wallet and immediately grab the right coins, it is a non-starter. Susies were too easily confused with quarters. Now, that could be fun if you're a wise-ass like myself - I used to get $20 in Susie's and then go out and buy lunch, etc. It was all the better when I could get some $2 bills and pay for stuff with a mix of $2 bills, Susies, and quarters - and watch the clerk's brain melt. I once has a Taco Bell clerk (the Taco Bell that is (was? I heard it is gone now) in the Tower Plaza across the street from the Burlington Mall, in Burlington, MA), back in 1995 or so, accuse me of trying to pass counterfeit money. He had to call his manager over - who just kind of shock his head and had to explain to the clerk that, yes, there really IS a $2 bill, and yes, those are dollar coins.
But, still, the fact that they worked for playing Confuse-A-Clerk makes them bad currency. Pretty much no one liked them, and they died.
Then a couple of years ago they came out with the Sacagawea coins, and they solved the big problem - they made them gold colored. They were the same size, weight, and density as the old Susies, and even had the same electrical properties - because they wanted them to work in any machine that accepted Susies. But they had a nice new design, and the color meant you'd never confuse one with a quarter in a handful of change. I used to get rolls of them and would use them regularly. But they never caught on, and I even ran into issues getting them from some bank branches which had stopped stocking the rolled coins due to lack of demand. So, eventually, I fell out of the habit of getting the coins since it took extra effort. Sometimes I get rolls of the coins, and $2 bills, just to satisfy my imp of the perverse, but that's it.
So now they're trying it again. And more coins on the market is a good thing - they last 30-40 years, while a dollar bill has an average lifespan of 18 months. But therein lies the problem - the dollar bill. To make the coins work they need to STOP MAKING DOLLAR BILLS! If they just ramped down bill production and allowed them to 'age out' of the money supply, then consumers and businesses would be pushed into using the coins bit by bit. And eventually no one would think twice about it. But they plan to keep producing the bills, thereby giving people no incentive to switch to coins. It is a Catch-22. People aren't going to want to carry the coins until more machines accept them, more stores give them out as change, etc. But businesses won't invest in any infrastructure as long as bill acceptors are still widely used, and cashier's will just keep giving out bills from habit as long as they're in the register.
This effort will probably flop, like the past two.