A turn-2 Empyrial Archangel might buy you three turns of safety against an aggro deck that's just starting to develop its board position, whereas one you've reanimated on turn 5 could die the very next time your opponent attacks
Late game Ooze is a beating as there are lots of things to eat and more mana to do so with
Keeping a card in exile means you'll always have it available when you need it, while keeping your hand free for cards you're more likely to use
Amethyst decks now have an extra, better top-deck game-winner outside of Merlin Goat
The cost of proxy cards varies depending on plenty of factors including print quality, materials used, and the resources used for the design
It can deal an explosive amount of damage, and under the right circumstances, win the game in just one attack while your opponent is at full life