In fact, it just lasts one turn
Frankly speaking, fusion spell cards are very effective during combat
The card's rarity is twofold: It's printed on the newly introduced Cosmos Holo, and it's one of very few non-ghost type Pokmon in the set
That is just fluff though, here is the more crunchy subject of archetypal facts: Attribute: Various (Dark, Fire, Water, Wind) Type: Various (Aqua, Beast, Beast-Warrior, Dragon, Fiend, Winged Beast) Levels: 2 and 8 Extra Deck usage: Xyz As you can see, there is no common Type or Attribute, which makes the use of anything Type- or Attribute-specific rather complicated
For Duels between members of different areas, both area counts will increase by 1, as will the count for total Friendship Duels