You don’t need this. If you’re on the fence, you don’t need this. These minis look cool, and they add a little wow factor to the game. But they don’t fit in the original game box because they are so huge, and they also don’t always fit on the game board. And that last part is a real design flaw.
The cardboard looks good and plays much better. So this set is only if you really like minis, want your game to be a little extra, but also want to struggle a bit while you’re playing to have all the pieces on the tiles.

Awesome game and the miniatures just add to the overall enjoyment of the game experience. I highly recommend getting the Creatures & Heroes expansion.