I wouldn't call "easier maintenance" a "user experience benefit". This reminds me of the talk "Is it really Complex? Or did we just make it Complicated?" by Al

I wouldn't call "easier maintenance" a "user experience benefit". This reminds me of the talk "Is it really Complex? Or did we just make it Complicated?" by Alan Kay. The complexity of the underlying problem, messaging, has not changed, but FB has made it a lot more complicated.