The magic of a returner in the manhwa and anime is very special. It usually comes with hidden powers and unique traits that drive the plot forward and make the character stand out. Also, it might have some rules and limitations that add to the complexity and excitement.
The specialness of a returner's magic lies in its rarity and the way it gives the character an edge in various situations. It might have unexpected effects or be tied to a profound backstory.
No. 'Manhwa' is a form of Korean comic or graphic novel, and it's not something that can be eaten in a literal sense. And in the context of leveling up in games or personal growth, consuming a manhwa novel as food is an absurd concept and has no real way of contributing to leveling up.
Well, it could be that the magic chocolate in the manhwa is a key element that leads to adventures or solves problems. Maybe it grants wishes or unlocks hidden abilities.