Importance of early childhood development. The emotional, social and physical development of young children has a direct effect on their overall development and on the adult they will become. That is why understanding the need to invest in very young children is so important, so as to maximize their future well-being.mportance of early childhood development. The emotional, social and physical development of young children has a direct effect on their overall development and on the adult they will become. That is why understanding the need to invest in very young children is so important, so as to maximize their future well-being.