Well, i havent got the chance to feel it yet, but perhaps it helps a bit when holding the phone during conversation?

I dunno about anyone else, but for me, whenever i am making a phone call, I,ll just grab the right side with the tip of my thumb and when the conversation is very long, my thumb will begin to sore. Perhaps that bump on the right side of the phone is to provide a "resting" place for the thumb when making a phone call.

A place for dediacted camera buttons and to keep sore thumbs away. Pretty much killing two birds with one stone.