What is the purpose of the Tree of Life according to YEC?

According to Young-Earth creationism, what was the purpose of the Tree of Life? Genesis 3:22 says that it would make whomever were to eat from the tree immortal. But according to Young-Earth theology, all creatures, Adam and Eve included, were already immortal prior to eating from the Tree of the Knowledge of Good and Evil. And as soon as they did so, God banished them from the garden, at least in part, to prevent them from eating from the Tree of Life. So why create this tree in the first place? What is its purpose?