Minecraft wiki entry for Hunger_management, associated text: Advantages
Melon farming is easy to automate.
Each melon block drops 3-7 melon slices, so you can quickly get a lot in only one harvest.
Melon slices can be crafted into glistering melon slices, which can be used to make a potion of Healing.
For food efficiency minded players, melon slices are almost never wasted on overfilling the hunger bar.
Melon slices can be crafted into melon seeds.
Melon plant stems will stay productive indefinitely with no need to replant them.