This ability works wonderfully with unblockable creatures and your Ninjas, letting you sneak damage in, refilling your battlefield with a new creature that also has a form of evasion, while at the same time giving you a powerful blocker to deter oncoming attacks
Its mostly a collector card
Terra herself has the ability to enter a trance that allows her to fly (at the cost of milling two cards) and whenever she deals combat damage, you may pay additional mana to resurrect creatures from your graveyard
A few enters-the-battlefield creatures and Conjurers Closet and/or Venser, the Sojourner would help that even more
They often have limited availability, so many of them are also worth a pretty penny
It's the Dragon Shield MTG Scanner app, and it does nearly everything a Magic player might want including collection management, language translations, deck building, trading, and acting as a real-time price guide