The Daily Goals are the equivalent of the daily missions in every other game - they will give you various rewards for doing certain tasks in game, so make sure that you check them out every day and do them, before they reset. They will help you gather a lot of EXP to level up, Activity Points (which add up to the daily rewards) and those will give you various rewards, from EXP Boosters to Coins and even free Superstar Draft x1 once you complete all daily activities!