I can see this being a 1-0-1 in ANY deck that plays Rare Candy, because if you can get that Meganium out, you can get rolling pretty quickly AND did I mention it states NOWHERE on the card that you have to follow the evolution rules. Boy am I loving this, and I'm going to go out and say it, but this Meganium is an 8/10 card.
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, in the first place.
I don't see myself needing to use a rare candy on Meganium, as opposed to just evolving my attacker.
Again, this is the same argument we saw with Shiinotic.
Because Meganium itself needs set-up, you are lowering your consistency overall.