Which is a great demonstration of just how highly valued VMAX cards are these days
Most of the cards that were initially priced high at release have dipped in value only a little bit, while several others have climbed up in price as the meta stabilized once players got their hands on the cards
It's essential to have a good balance of both to ensure you have quick access to attackers early in the game and also the power to handle the late game
If you, as a Group Slug player, want to stay in the game as long as possible and do as much damage as you can, having ways to ward off attacks without having to try too hard is a good idea
The mutate cost is high, but the payoff is more than worth it, especially since it's easy to obtain that much mana with traditional green ramp spells
Karn is fantastic design and that is hard to do on a colourless card