都对。to在这两种句型中，意思和用法不一样。
appeal to sb里to意思是对某人而言, in sb's view。sth is an appeal to sb等同于，sth is an appeal in sb's view. 或者 sb thinks sth is an appeal.
而appeal to sth里to表示一种从属关系，相当于of。比如the key to the door. There is an appeal to sth等同于sth has an appeal.
中国同学长期用中文来学习英文，很容易误以为to这个介词只有一种意思。其实它在不同句子和语境中意思可能千差万别。
