Let me start by saying that I really dislike the design of the GSIII.
That being said, and to play Devil’s Advocate a bit, it is most likely that the design for this was planned way before the ICS addition of the on-screen stuff like you mentioned. Perhaps they didn’t have the time to change the hardware/software design before launch? I know that’s a weak argument, trust me. However, it could be that this is at least some reason for having the hardware buttons (especially the menu button).
