The obvious disadvantage of this process, as with all forms of usury, is that the tax collector is inserting himself in a transaction to make a profit at the expense of the borrower (taxpayer). This creates a serious conflict of interest. For example, lending money at interest was generally frowned upon during most of recorded human history, however tax or rent was acceptable. Therefore, once the lending of money through banks was formalized by the governments, then tax collection must have been included to pay the national debts that make fractional reserve banking work. So we went from governments selling the right to "tax" to private people (whether feudal or mercantile) to allowing the same group to create money to lend to the government (for free of course) and then the government must collect taxes to repay the debt and support the currency.