What is the key difference between categorical grants and block grants?

Categorical grants lack any true congressional oversight, and block grants require a lot of congressional oversight.

Categorical grants are reflective of the dual federalism era, and block grants reflect the cooperative federalism era.

Block grants provide states with more leverage and power over how to spend grants$-$in$-$aid than do categorical grants.

Block grants can be spent on any policy issue, no matter what Congress allocated the money for initially.