You're definitely caught in the hype for this one.
Rare Candy is already a space commitment for any stage2 deck.
Usually, the stage1 is replaced to mitigate this.
Further increasing the slots used just to evolve your attacker, is a bad idea.
Especially when Meganium is not a consistent option...
I think there is a misconception of value here, regarding Meganium's ability.
While, on paper, it seems incredible... in practice, it will almost always be clunkier than Rare Candy.
Especially since, being a stage2 itself, you'd want to Rare Candy Meganium anyways.
If it was a good attacker, it...