Direct Democracy cannot work if citizens are allowed to vote the country into deeper debt. What if all approved programs and services had to be correlated with a source of funding? Public works might be paid for by fiat money, as well as partially supported by workfare. Tariffs might pay for basic government operations. Hospital health care might be partially paid for by a consumption tax on products that contribute to poor health. If citizens want war, their personal taxes would have to increase accordingly.
Imagine next April you are preparing your income tax return and you find that you are now able to decide where your tax money goes. What would your budget pie chart look like?