I recently acquired the Irithyll Straight Sword and see that it does Frost damage. When fighting a boss, I noticed that eventually gave me Frostbite, though I have no idea what Frostbite actually does. Checking the wikis has been inconclusive, mentioning that maybe it hinders stamina regen.
What does Frostbite do? If it only slows Stamina regen, does it even matter in PVE?