mike wightman
SOC-14 10K
On the frontier they have some political autonomy, but they are still bound to use the Imperial credit for their monies
The unit of exchange in interstellar commerce, and between the Imperium and the member worlds, shall be the Imperial Credit. The Imperial Credit shall be valued independently of the value of any coin, currency, or value of any member world. The Imperium shall have the responsibility and power to control the value of the Imperial Credit.[/credit]
Like I said, it would be like each US state having its own currency pegged to the Federal dollar, which is a recipe for financial disaster.
Lots according to google.