Reanimator decks typically use removal-resistant cards like these along with a whole host of cards that come back from the graveyard, making it almost impossible for opponents to remove their threats
I wish it had more colors to have more weird counters from something like blue or green (the other colors in this precon deck, ahem), but it's pretty cool
You can drop her, and then when you need, monstrous her up
With Elven Council being only 2 colours, it makes Mana fixing a lot more easier, solving a potential bugbear for new players
If that wasn't enough, if you cast a spell which is multiple of these MTG colors, you get each of the abilities that share a color with the card cast
This situation doesnt come up that often though, which is why I valuable Night Whispers flexible mana cost over Sign in Bloods ability to target other players