“For God grants His creatures not only their existence, but also the dignity of acting on their own, of being causes and principles for each other, and thus of cooperating in the accomplishment of his plan.” (CCC pgs. 90-91) God loves us enough to let us participate in His plans. We were created not as puppets, but as free, intelligent people, and we are invited and encouraged to play a part in God’s work.
It makes sense, actually. When you are part of a family, each member plays a role to make the family complete. Some detract from the love and value of the family, while others are the pride and joy of it. We are all part of God’s family, and therefore we are members of creation, united for a common cause, with God as our head. It is good to be loved this much!