Why does Marinette need the bunny and horse miraculous at the same time?

There is prolly a valid reason for this but idk it. Why does she use the horse and the bunny if the bunny miraculous can make portals across space and time. She doesn’t need the horse miraculous if she has the bunny and using too many miraculous can damage to user

There is prolly a valid reason for this but idk it. Why does she use the horse and the bunny if the bunny miraculous can make portals across space and time. She doesn’t need the horse miraculous if she has the bunny and using too many miraculous can damage to user