Although a one dollar coin is three times as expensive to make, it lasts more than 17 times longer than a dollar bill. It costs 5.4 cents to make a $1 bill and it lasts on average 21 months. A $1 coin, in contrast, costs 18.03 cents and lasts for 30 years. Although coins are thus more economical from a production standpoint, there are additional costs from the coins' much greater weight. Coins are more than eight times heavier than bills and a lot less convenient to use by people and businesses.
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The single problem here is that machines that take coins have never been upgraded to take dollar coins.
Japan refused the dollar coin initially, but readily accepted it once vending machines started allowing their usage.
Same with their five dollar coin, and there was a lot of unhappiness over it, until the coin machines started accepting them.
Now everyone in Japan loves the one and five dollar coins and the smallest bill they have is a ten.
The same would work here, but needs to be implemented with coins that don't look like quarters, and if it had already done, everyone here would have already accepted the gold toned president dollars of a few years back.