The Power Nine were only printed for the very first core card sets, and the group includes the Black Lotus, Ancestral Recall, Time Walk, Timetwister, and the Mox jewel cards: Mox Pearl, Mox Ruby, Mox Emerald, and Mox Jet, as well as the Mox Sapphire
For example, getting a free 3/3 creature token over and over again lets you use it to power the kind of sacrifice-based strategies you often find in black (even Proliferating again if you use Throne of Geth)
The only reprint worth over $10 is Door of Destinies, and Id say its safe to assume that original cards may lose a bit of their value with time
As per usual with Pokmon TCG sets, Twilight Masquerade comes out in Japan a month ahead of its US release
Why grade your Lorcana cards
Escape's permission doesn't change when you may cast the spell from your graveyard