The following Q&A is excerpted from Clifford Mishler’s Coins: Questions & Answers:
Q: Why did the Mint make the mistake of making the Anthony dollar almost the same size as the quarters?
A: The principal reasons were economy, and the feeling that the public would not respond to a bulky, cumbersome coin of the old dollar size. They were right about the second reason, but the public rejected the coin anyway, at least in part because it was readily confused with the quarter. The coin was originally envisioned as a multi-sided coin—11 short facets, which were ultimately represented on the border with a perfectly round circumference—but what resulted was a round coin, as it was concluded that the round shape was preferable for vending machine applications, which likely adversely influenced user confusion and its acceptance. A contributing factor may also have been the coin’s reeded edge. The quarter is roughly equally larger than the nickel, which has a plain edge, but since both quarters and Anthony dollars have reeded edges, many of the latter were unknowingly tendered as quarters, so when received in change they usually were returned to the banks, rather than maintained in circulation.