That very pretty edge chamfer is as vulnerable and delicate as anything I have ever seen on a consumer product at this price point. I wouldn't dream of using mine regularly without a case.
It's a design feature that is certainly beautiful, but the vulnerability to damage is too extreme for caseless use- defeating the purpose of the feature in the first place.
Even if the body were stainless steel instead of aluminum, it would be unacceptable. I would be a lot happier with something that isn't quite so delicate.
I feel it reflects a certain disconnection how these items are used in the real world, on the part of the very talented Mr. Ive and his team.
Love their vision, not always wild about the execution. (Sharp edges on the rMBP palm rest come to mind, too).