Each Replica Monado has its own strengths and weaknesses. Also, there are ways of defeating the monsters at lower levels, especially if you try to get the achievements for doing so. The Replica Monado quests also give a nice chunk of experience points. Some people also like the challenge or want the replicas for completion's sake.
Quests are up to yourself whether or not you do them. That's the handy thing about the replicas, you don't actually need them.
Yeah it wasn't neccessary i just went ahead took down Zanza and started new game +. (Thanks!)
I have tried to get the replica monados but i realised that I have to be at a ridiculously high level to even be able to fight some of those enemies. And when you beat the game you can't even use them because you can only use the Monado III. So my question is what's the benefit in attempting to attain these replica monados.
im lvl 99, beat the game multiple times, haven't gotten replica's yet. getting rudra, abyss, and dogma, nothing stops me. I AM GOD. sooooooooooooooo literally, monado III all the way to rudra, abyss, and dogma.
Another way is to have Riki use Yoink! on the enemies you can't beat. (Roly Poly at the start of the fight to possibly topple the enemy, and get a guaranteed steal is very helpful.