It is there, but it only ever seems to work at times when you don't want it to.
Honestly, as someone who's played controller my whole life, all if does is get me killed, since it doesn't understand that projectile champions don't want to be magnetised to a target all the time.
Would be nice to have it removed, or have an option for those who don't actually want it at all.
Min Smooth Frame Rate basically checks if your frame rate goes below that threshold. If it does, it will lower your max frame rate automatically. Or atleast that's what it says in Unreal Engine's documentation.