What is the significance of the battle or attack of Doolittle's raid on Japan

Doolittle's raid was a morale booster more than anything. After the attack on Pearl Harbor, Americans needed to demonstrate having the ability to attack Japan. Doolittle's daring raid launched from carriers at sea and brought the war to the Japanese mainland. While the damage it caused was not significant, the fact that 'Japan was not "untouchable" was proven and changed the attitude of the entire nation.