One advantage the federal system of government has over confederal is the ability to maintain a stronger central authority that can effectively manage national issues and coordinate policies across the states or provinces, which helps to maintain stability and unity in the face of regional differences.
One advantage the federal system of government has over unitary is its capacity to accommodate regional diversity and local governance, allowing states or provinces to tailor their laws and policies to better suit the needs of their populations while still being united under a national framework. This can lead to greater responsiveness to local issues and increased citizen participation.