I didn’t say they were good at it.
This is a small island in the center of a big marsh. Storms and water levels are slowly undermining the tree and reeds.
This has always been a good place for Alligators to get dry and still be close to the water.
As large as they are, with no predators at this size, they still want the safety of diving under water to hide.
This was photographed in a wildlife management area so by default they are safe. Besides look how big they are. Whatever they need to hide from I do not want to meet.