What are examples of Mary Shelley's trying to prove in Frankenstein that beauty means more to society than knowledge and good deeds?

There are several instances in Shelley's Frankenstein which point to this idea. When Victor first animates his creature, what horrifies him about it is its appearance: "a mummy again endued with animation could not be so hideous as that wretch." He does not pause to observe whether he has succeeded in creating a being of good character, nor does he hesitate to consider whether his own conduct in making the creature in the first place was commendable. Rather, because his creature is physically "hideous," he is so bitterly disappointed in his work that he abandons the room in a fit of distress.
Later, in the Creature's own narrative, Shelley depicts a sensitive and intelligent being who, like any human, enjoys the pleasant sounds of birds and admires the aesthetic beauty of the moon. However, when he encounters people, it is not the creature's internal character to which they react, but his physical appearance. An old man, "perceiving [him], shrieked loudly, and...ran across the fields with a speed of which his debilitated form hardly appeared capable." This experience is repeated when a whole village "fled" and "attacked" the creature, based entirely on his appearance, causing him to flee. None of these people knew anything of the creature beyond his physical appearance, and the creature longs for "kindness" of the sort he witnesses among the villagers, but knows it will not be offered to him. Instead, he watches from a distance and learns speech from the people he observes. Even the creature, when he eventually sees his reflection, can see only "the deformity of [his] figure" and views in his own image "the monster that I am." His physical deformity has "fatal effects" in that it influence every interaction he will ever have in his life.
The creature's own reflections articulate his feelings about man being made in God's image, and they focus upon physical beauty and the way in which it encourages sympathy:

Accursed creator! Why did you form a monster so hideous that even you turned from me in disgust? God, in pity, made man beautiful and alluring, after his own image; but my form is a filthy type of yours, more horrid even from the very resemblance. Satan had his companions, fellow devils, to admire and encourage him, but I am solitary and abhorred.

Shelley's frame narrative allows us an insight into the Creature's true character, in which we can see that he is, in fact, a sensitive, intelligent and sympathetic being, but to the world—and even to his own creator—he is a monster because of the way he looks. Nobody he encounters in the story spends even the time to appreciate his internal landscape because of this "deformity." Meanwhile, Victor himself, whose deeds are conducted in the dark and in "charnel houses," concealed from society, is never perceived as the villain he truly is. His conventionally attractive appearance allows Walton to view his face as something "lighted up" even in its worst states, while the Creature is never offered the benefit of the doubt.