Star Trek: 10 Things You Didn’t Know About The Guardian Of Forever
10. It Seems To Enjoy Testing Its Subjects
Much of Emperor Georgiou's experiences with Carl, as the Guardian calls themselves in Terra Firma, are in the form of a test. She is suffering the effects of being both out of time, and in (from her perspective) an alternate universe. Carl may well be the path to a cure that she needs, but he isn't about to just hand it over.
He sends her back to her own time and universe, testing her to see if she really does have the capacity to change. Once he ascertains that she does, he agrees to send her back to a time when her universe and the Prime universe were more aligned.
There are echoes of the Guardian's first appearance here, not simply in the newspaper and the donut. Kirk and Spock, having successfully rescued the future, and McCoy, are offered the chance to use the Guardian to explore history as they see fit. It is they who decided to decline, with the pain of Edith Keeler's death still too near.
Yet still, this version of the Guardian, much like its later appearance as Carl, seemed more intent on testing its subjects than on passing judgement from the off.