> But a corner frame mechanism like the 2D edit frame is more snappable since you can actually snap the corners on to other objects in the model when you drag them.

Yes, I like those. I've learned that depending on which way to move the corner handles, you can effect the way that the (z) hidden directions on an object can be scaled also.
I utilize this feature when prepping profile rings, so that I can either shrink them proportionally or just by height.