"Is preferred" is a sweeping generalization.
My home region in Virginia has some pretty horrific wind gusts, and the long door-side awning is a monster untamable. Actually, in a previous TT, a sudden storm at 2 am caught the awning, flipped me out of bed and would have rolled the trailer over had the support arms not broken, letting the entire awning go over the roof.
I'm not saying you should do as I do. However, I wish ALL of my awnings were short and manageable.
More fasteners through the skin... sure, but less stress overall on those fasteners.
What I really wanted was rivets, by heaven! Rivets. To get on with the work... to stop the hole.