Well, I've also asked that to myself. Why do i describe him as a beautiful person, rather than good-looking, or hunk or handsome? I really don't know. All I know is that when I describe him "beautiful," it's his physical appearance. Perhaps because he has cool wings. And angels in comics are usually female characters. Maybe that's the reason. But one thing is for sure. He looks awesome.
How about you? Why do you describe him beautiful?
Check out how cool Archangel looks on this video: