If an effect instructs you to transform a modal double-faced card on the battlefield, it transforms only if its other face has a permanent type (that is, if its other face isn't an instant or sorcery)
For every argument that it lets color combinations like Boros catch up with Green by playing cards like Mana Vault, Sol Ring, Smothering Tithe and Mana Crypt, theres a fair argument that Green decks also have access to these cards, and that it means Boros is no better off
Early on, you get solid black mana production with the added benefit of being indestructible
Because Elsa is a popular character and this was featured in the first booster set released to the public, this card is a valuable addition to your collection
Ever since Alpha, Green got heavily played card draw machine Verduran Enchantress that draws you a card when you cast an enchantment