These exercises can help children calm down, become more focused, fall asleep more easily, alleviate worry, manage anger, and generally become more patient and aware.
There is something we are all capable of but usually don't cultivate intentionally. Why not start young in training those capacities?
An important aspect of mindfulness is the ability to tune into our intuition, our inner wisdom. An intuition often shows up as a "gut feeling" about something that you find out later was completely accurate.