Giving that song an 11 just screams that you didn't give anything else a chance
First, I said it's my provisional 11. Something else could still snag it. Off the top of my head, Perfect is a contender.
Second, it is really an amazing song. I gave it a 10 in my X Factor Losers rate where it was against a lot of other really incredible songs like Once, My Wicked Heart, Stay, With Ur Love, Want U Back, Oath... from two of my favorite albums of all time. That's how highly I regard it.
Third, it's not a matter of giving other material a chance. Beautiful is exactly the kind of song I like - I am giving their other songs a chance, and I'm sure I'll like a lot of the ones I don't know. But I know that the kind of song that sounds best to my ears is a power-pop/pure-pop anthem like Beautiful. Teen-pop is denigrated a lot, even here on Popjustice, but it's honestly what I like the best, and that's just as valid as liking any other genre.