The following is excerpted from Clifford Mishler’s Coins: Questions & Answers
Q: As the American colonies were once British possessions, why did we not adopt the sterling currency system, as did most other countries that subsequently emerged from British domination?
A: The reason was not, as some have suggested, to disassociate the United States from everything English. The Founding Fathers adopted substantial portions of English law, religious practice, and social and political philosophy, along with weight and measurement standards.
Despite its arbitrary and cumbersome complexities, the sterling standard would quite possibly have been retained had British America remained a colony of the Crown, although efforts to express its value components in terms of the more prevalent Spanish coinage had already created a chaos of intercolony exchange rates. The adoption of a currency system more suited to the economic reality of the colonies/states was facilitated by the philosophical atmosphere of the War for Independence, which conditioned self-reliant men to cast off the shackles of tradition and initiate changes with little nostalgia for customs of the past.
England had never furnished more than token quantities of sterling-standard currency to the colonies. The coins of the colonies were a mishmash of English, Spanish, French, Dutch, and private issues. An effort was made by the various colonial governments to express their values in terms of sterling denominations, but the assigned values varied from colony to colony, making intercolonial commerce a horror of reconciliation and adjustment.
The Spanish dollar, being divided into eight equal parts, contained an inherent suggestion of a more logical system. A decimal currency with subdivisions of 10ths and 100ths, wherein the American and Spanish dollars would be equivalent units, was both desirable and logical, and the intellectual climate was equitable for the inauguration of change.