This is to ensure that there are enough checks and balances in the system to prevent the country’s decisions from being solely taken by just an individual in order to prevent mismanagement of public funds.
Explanation:
In the Article I of the US Constitution there is a provision that prevents the president from enacting a federal budget on his or her own, without the consent of other branches of the federal government.
This is to ensure financial accountability and prevent the high risk of misappropriation of funds if the President had the sole power to do so.