Why learn Bhagavad Gita?
Bhagavad Gita is the only Hindu scripture with answers from God himself, for every question that a person has, on life and living.
Just as Arjuna is reluctant to fight on the battlefield, troubled by attachment and fear, we face challenges, every day, that we are reluctant to deal with. Krishna's discourse to Arjuna helped him realize his responsibility not just to himself and his family, but to the entire society.
Learning this same discourse from Krishna, in the form of slokas, will help us as adults, in understanding our responsibilities.
At the same time, children will learn how to take on and succeed in a great challenge such as memorizing all the slokas in the Gita. This treasure-trove of knowledge will stay with them, throughout their lives. And when they begin to understand each sloka's meaning, it will help them make the right choices, as they face the many challenges in growing up.
Knowledge of the Bhagavad Gita is so powerful, that Adi Sankara, in BhajaGovindam, has written that a person can attain Moksha by learning just one sloka from the Gita.