Master's Key The Master's Key was created more recently than most rare Pokmon cards out there
Extra land drops are very hard to take advantage of in Limited, especially by the turn you play this, because you just run out of lands to play
I like it better than Reclamation Sage usually since it's an instant speed removal spell and has the flash synergies to block and trade as well as destroy on arrival, and it has a bigger butt
This is generally found in decks that are intending to reanimate a large game ending creature early and protect it such as Ulamog's Crusher
Thanks to them, you gain victory points (lore), use their unique abilities, or destroy opponent's characters
They provide the convenience of shopping from home, and many sites allow you to filter search results by set, rarity, or condition, making it easy to find exactly what you're looking for