Why Doesn't God Always Use His Superpowers

“The Personality of Godhead heard the appealing voices of His friends, and casting a pleasing glance over them, He began to answer. By speaking through His eyes, He impressed His friends that there was no cause for fear. Then Krishna, the supreme mystic, the powerful Personality of Godhead, immediately swallowed up all the flames of the fire. The cows and boys were thus saved from imminent danger.” (Krishna, The Supreme Personality of Godhead, Vol 1, Ch 19)