When placed on an evasive creature like Spyglass Siren, it allows the player to draw a card each time they deal combat damage
Green has some ways to get through in combat that aren't trample, and quite a few cost the 1 mana we are used to paying for Hypnotic Siren or Zephyr Sprite
In addition, when these are on the field they can provide all manner of handy bonuses, such as spell protection, card draw, and special summoning capabilities
In standard mode the player's deck can only use cards which are legal in the current standard rotation (each year older cards are retired from play)
That would be a valid question, were things quite so black-and-white
Fountainport is a very flexible utility land in a deck that pumps out tokens