To steelman the case for its removal:
1. Do not reward poor performance (American's are ~40th best in the world for education, despite spending the most)
2. Remove incumbent bureaucrats who may have agendas
3. Giving this responsibility to the states lets education be more closely aligned with state values
Downsides:
1. People tend to dislike change, especially for change's sake
2. Duplication (each state will have to do things that could be done just once if done nationally)
3. Potential loss of shared curriculum (having some common background in knowledge, culture, reading) helps understanding and communication