No, the A in ARC means you don't have to write retain/release yourself anymore, the compiler inserts these calls for you. Very different concept from the optimization you're describing.
I fail to see the difference to any other RC implementation, including how languages like VB handled COM RC in the 90's or some of the early Lisp implementations.
What is the technical difference at implementation level?
It is like VB 5/6's RC. And it is unlike RC implementations in which the programmer has to write the retains and releases. It is not, though, a compiler optimization.