I have a question to the Ranger's Hunter archetype features.
At 3rd Level I got the feature "Hunters Prey" and chose "Colossus Slayer." From the description (PHB p. 93):
Your tenacity can wear down most potent foes. When you hit a creature with a weapon attack, the creature takes an extra 1d8 damage if it's below its hit point maximum. You can deal this extra damage once per turn.
From my understanding I can deal this to every creature if it's not on maximum hit points.
What use has then the favored enemy? I didn't find anything where abilities only apply to favored enemies. Is this Colossus Slayer ability only usable on creatures which are my favored enemy, or is the favored enemy just for roleplaying?