Originally Posted by xiaoman1

This may have already been mentioned, dimpling provides a number of advantages.....One, being strength the other is aesthetic......hiding small bumps and bruises that occur in production and daily use.

dimpled....hide a dent

dimpled 2
Just as many of us that want to "roll" out (hide) a dented tube because our eyes are drawn to the small imperfection a dimpled surface will camouflage a damage area.
I suspect bicycle fenders were prone tho the inadvertent clash with a rock.
JM2C's, Ben