You can mill this card or discard it to another effect, and still unearth it with haste to catch someone off guard, and its much better when you have discard synergies
Planeswalkers with good board control options and high loyalty counts are hard to deal with, much more so than cards like Elesh Norn or Griselbrand
If an opponent is instructed to put a card into their graveyard without using the word "mill," The Water Crystal's second ability doesn't apply
The fact that Nissa is drawn to be bending backwards unnaturally shows how dire things are for the rest of the Magic multiverse
Most often, they are low-power, high-toughness creatures, which means that without some extra support, they are usually good at blocking (and making mana, for some reason) but aren't very good at actually killing the opponent