The title makes no sense

Only his physical form is there.

Thought exactly the same thing while watching the movie.

The best interpretation i can come up with is that he never intended to stay in Vegas, but to eventually leave it behind with everything else, including his own life. His aim was to go to Las Vegas in order to leave Las Vegas.

But i agree, it's a bit convoluted, which only adds to the charm of the movie, as for me.

People who don't like their beliefs being laughed at shouldn't have such funny beliefs

Answered on multiple other threads. The title refers to HER, not him. In the end, what is she doing? She can't go back into many of the casinos, she's lost her house, she's alone and sitting on the curb... she is LEAVING. The movie is about Sera, not Ben.

The title obviously refers to Ben (Cage) leaving Las Vegas -- which he does at the end after drinking himself to death.