It's needed in case a player's main card is put into a library, hand, graveyard, or exile
He drilled through the floor of his Furnace Layer birthplace and emerged in the Hunter Maze
Curses are enchantments you put on another player that either persuade your other opponents to target them, or directly punish the cursed player in some way
Removal and card draw is something that every deck needs, stapling them together helps further your gameplan faster than the rest of the table
Including ways to untap a creature makes Pride Sovereign more consistent, since you dont have to worry about the downside of exerting it
You cant really play this white enchantment in decks with more than two or three colors because those decks tend to cut basic lands for mana-fixing lands, but any deck with a healthy number of basics can easily exile a creature or planeswalker