Comment by Puppy_Reader on I need sleep

@I need sleep The Task was meant to give him a better perspective in his loneliness, it isn't about the cleaning, it's about learning to work with others and let others in his lonely world. You may call it however you want, but it isn't child labor when the child himself wasn't forced to do it, he could have skipped the whole thing since it's considered "Training" not order, and it worked, the child is full of sadness and grief, and has been alone even during his days in the academy, so the Tower mage made him interact with the staff learning to have bonds with them and enjoy his life without the presence of magic. 

Also War Mage is an actual occupation, it basically makes him the equivalent of a Knight, War Mage (Combat Mage) is a guardian who's duties is to protect the kingdom. The promise is meant to show the Tower Mage sees and acknowledge his potential, and using the Title of War Mage as a goal he can attain, and that he'd be able to purchase his old property from her through that.
She sees the MC as a Genius with his Rapid growth, and that in her eyes the MC can become something greater than a simple War Mage, it's just the bare minimum of his potential.