This is because Sec 31 of RBI Act, 1934 says so. "No person in India other than the Bank, or, as expressly authorized by this Act the [Central Government] shall draw, accept, make or issue any bill of exchange, hundi, promissory note or engagement for the payment of money payable to bearer on demand, or borrow, owe or take up any sum or sums of money on the bills, hundis or notes payable to bearer on demand of any such person: Exception to above is cheque. Trying to decode the intention: Government wanted to reserve currency (which is also a kind of promissory note) rights to itself / Bank so that alternative mechanisms do not emerge. Also, bill of exchange is mainly to facilitate trade and structured as contractual obligation. So, usually there must be either 2 parties or a definite time.