Later in the game, if you cast it for the full 5-mana creature, you get up to a 5-mana permanent back
Pokemon coins are a nice little bonus collectible, which also have a practical use in-game (deciding the first player and the outcome of using certain abilities during play), and the mini portfolio is also a good, if short term, way of storing your favourite cards
Second, some people just like to collect things
Spell/Trap: Send the top card of your Deck to the GY, then if it is a monster, except "Armed Dragon Zero", this card gains that monster's effects until the End Phase
You can pick between 2 and any amount of players
Trainers can expect to discover new strategies and combinations that harness the power of Terastal Pokmon