Except the exchanges will be heavily regulated and required to record your identity, and converting them to A-coins will be illegal. Even if enforcement is spotty, one can't take the process for granted and the common view will be that A-coins are for criminals. Primarily functioning as a temporary medium of exchange for identity-based systems means it's only a matter of time until the ambient authority infects the system through the exchanges, imposes changes to conform to its view of the world, and demands respect as middle man and final arbiter. The only way to create an anonymous digital currency is to concurrently develop the anonymous digital economy.