From a technical perspective, these strategies appear to have been effective. When the system operates at high volumes, the cost of an individual transaction is low, perhaps a fraction of a cent. Further, the system adds only about a second to the total transaction time. Another source of expense in any payment system is the cost of handling complaints and questions from the consumers. A customer service operation requires many people, telephones, and computers.
Customers are usually confused or irritated, so the interactions are far from efficient.
Each customer service call costs a few dollars, sometimes more. If there is no way to resolve a dispute amicably and quickly, there might be several calls associated with the same transaction. Customer service becomes a serious burden in the micropayment world. Even if the nominal profit margin is high on individual micropayment, the absolute margins are rather thin. A single customer service call can easily wipe out an entire year's profit on that customer account.