Greater color uniformity between batches. Anodizing is much harder than paint. Anodizing is better for aluminum in high traffic areas where the coating is subject to physical abuse and abrasive cleaners. Coil painted sheet does not craze as badly when fabricated. Anodizing can not peel off.
Coating is actually part of the metal.
Better chemical resistance to mortar, strongly acidic cleaners, and strongly alkaline cleaners. Deeper metallic color than possible with paint. Generally anodizing has quicker delivery.