The Butterfly Effect is on now....
IMDb Video: The Butterfly Effect
The purpose of time travel as explained in that article by the two physicists, is to prevent the occurrence of something that may have disastrous consequences (formation of the boson particle and black holes).
I suppose time travel could also be for joy riding, as in "Back to the Future" (etc).
Although time travel technology (if it is possible, which many scientists believe it is), may not currently exist now, it may in the future. And it is FROM the future that something occurring today may have originated.
SS