While this can be a little dangerous (especially against Phelddagrif decks), you can harness this effect to enable some extra mana for cards like Vampiric Tutor, Entomb, Infernal Grasp, or Village Rites while still tapping all your lands on your turn
If the target is a colorless creature or planeswalker, you won't gain any life
It can tap for a lot of mana
This enchantment essentially gives us a second copy of our battlefield for seven mana, which seems fantastic in decks that can pay its cost effectively
If an opponent tries to destroy a creature with all of your Auras and Equipment attached to it, for two mana you can move all of them to another creature, or spread them between several creatures
Metang allows you to rapidly flood your Pokmon with Metal Energy by pulling all of the Basic Metal Energy from the top 4 cards of your deck