Generally the rarer the card, the more Tokens you get (with a few discrepancies and inconsistencies)
In the case of artifacts, its especially dangerous because you can fill your deck with 0-mana artifacts (Ornithopter, Memnite) or artifact lands
Charizard ex's Special Illustration Rare variant card 199/165 is on the list for most expensive Pokmon cards in the 151 set, coming in at a whopping $166.49 USD market price on TCGPlayer at the time of writing
You must still follow any timing restrictions and permissions for the creature spell you cast from exile
Combine other products to make your deck even stronger
With the Shift keyword, rather than costing five ink to play Kida, Protector of Atlantis can be played for just three ink if placed on top of another character named Kida - thereby making it a lot easier to get this card out