The Banana at seasons 1-10 will completely or almost completely fill up the Sacrificial Meter, which is very useful if you start with bananas, enabling you to easily let your island grow. When eaten, the banana replenishes 2 hunger and 2 thirst.
Because the trees drop 3 bananas each harvest, it can be easily farmed. Around 2 trees in the start is a good way to start farming bananas. It is recommended to have a few Granaries or a Storage Basin.