Equality between states and the country
Fedaralism is the sharing of power between a central government and the states that make up a country. The delagates of the constitutional convention wanted to create balnce among the states. Therefore, they created federalism. The other federal systems the states had more power. Each state must obey the authority of fedaral, or the whole country, government.
To make sure no one is better than another. That is a matter of opinion. Suffice it to say that each has its positives and negatives, and as such, the choice for which to use in any particular nation depends on the nation, its people, its existing political subdivisions. The United States was a series of colonies under the British unitary system; upon the execution of the Revolution, the United States became a confederation under the Articles of Confederation; and when that system proved unsuccessful, it was transformed into a federal system by the Constitution.