Teaching games - small streamlined decks tend to focus on one strategy, and use a few specific tactics, mechanics, to get there - a larger and more unfocused deck can be used to teach new players broader groups of mechanics and the way they interact better than competitive decks can
It only deals 30 damage, but it also returns Shaymin and all of the cards attached to it to the player's hand, effectively allowing them to make use of Set Up indefinitely until they either run out of cards or Shaymin runs out of HP
You defeat your opponent if you reduce their life points to zero, or if they've run out of cards in their deck and need to draw one
If an ability changes a cards creature types then it doesnt modify any land types, artifact types, or whatever else the card might have
More than 140 different sets, dozens of formats, and about 30,000 cards can be very confusing