If the intention is for farming materials to be an activity that the final game promotes rather than allows, then yes.
One threshold could be defeating that type of enemy without taking damage. You could cheese it and play the combat real slow but if you're willing to do that you're probably willing to grind materials.
This would likely break down at enemies that deal poison or bleed damage as that seems unavoidable. One work around could be end the combat with full health without having used a healing item (health cards allowed).
One thing to note, it seems like hunting in the enchanted forest uses a time bar, but hunting in the cave does not. Not sure if that is intentional.