The gold dollar (1849–89) was a tiny coin measuring only 13 mm making it difficult to grasp and easy to lose, a serious problem when a dollar was almost a day’s wage.
Dollar coins have found little popular acceptance in circulation in the United States since the early 20th century, despite several attempts since 1971 to increase usage of dollar coins. This contrasts with currencies of most other developed countries, where denominations of similar value exist only in coin. These coins have largely succeeded because of a removal (or lack) of their corresponding paper issues, whereas the United States government has taken no action to remove the one-dollar bill, due to intensive lobbying.
The lack of popular support for contemporary dollar coins may stem from the fact that they are not accepted by most vending machines, which limits their usefulness to the public. Cash register drawers would likewise need to be redesigned with an additional space to accommodate dollar coins.
The United States Government Accountability Office (GAO) has stated that discontinuing the dollar bill in favor of the dollar coin would save the U.S. government approximately $5.5 billion over thirty years primarily through seigniorage.
Article Source: en.wikipedia.org