"Looks are overrated"....stupid?

When Brad mentions this, the narrator tells "Only someone who took his own beauty for granted could say something so stupid".

I was never quite sure what was meant...

-how he underestimated the importance and impact of good looks?
-how he was not complimenting/comforting Sarah with this, who supposedly has a lack of good looks (hard to believe with a miscast Winslet...she's too pretty for this role)?

From Brad's point of view it seems he was telling the truth, having been with a knockout and knowing it was not all that to have such a woman as significant other. It did not seem so stupid to me but I guess it was just the clumsy thing to say to a woman like Sarah?