Luck can help you out in critical moments, and it can change everything.
But like the other attributes, it is not an all-powerful ability. With increased critical hits, you'll be able to handle even the most giant of Super Mutants.
And you'll also get an increased chance of hitting the jackpot! Luck also seems to play a role in how frequently the Mysterious Stranger and Miss Fortune perks kick in to save your ass in tight situations!