Castiel never thought about the way vessels or humans in generals looked to the reduced abilities of the few human senses. Priestly's need for constantly changing his appearance was just an oddity the angel filed away as part of this specific humans personality, the same way he preferred to his given name.
Coming from a deeply religious background before Priestly had decided to live on his own made it surprisingly more difficult for Castiel. The knowledge that Castiel was an angel had not been enough for young man, the information that he would help his fellow humans changed that easily.
