Given it a bit more thought, and the other problem with the bends vs 90 deg. fittings is breaking strength under load.

The back (the part not pictured) will have one, maybe two vertical supports which should help, but having those bends means it would take a lot less load (snow) to push them to the critical point where the metal creases and then snaps.

If I lived somewhere down South, using bends like this would probably be fine.