How did unrest in hungary and czechoslovakia during the cold war period benefit the usa?

I would say it was mostly a benefit of "moral advantage" - meaning that the US  would have a better image in the eyes of other countries.

The context for this is the Cold War - a conflict between the communist countries, led by the Soviet Union, and the capitalist countries - led by the US. The unrest in Hungary and Czechoslovakia showed to the world that Soviet Union is abusing its power in the region, which gave the US better arguments for military intervention in countries where the Soviet Union was trying to establish a communist rule.