Live by Night
The key question behind Live by Night isn’t so much “Why did they bother?” as “What went wrong?”
Time travel, as we all know, is (1) impossible in any real-life, non-quantum sense, and (2) irresistible to filmmakers. Rian Johnson's Toronto entry "Looper" asks us to accept it as a premise, and you know what? It's handled more realistically here than anything in the plots of the average superhero movie. One of the strengths of time travel is its demonstration that if we could travel through time and meet our parents or even ourselves at an earlier age, it could be an unbearably emotional experience.