It is part of a small group of "Shining" cards introduced in the Neo sets, which depict the Pokmon in its alternate coloration (Shiny)
Ideally you want to be at four or five such cards (in a forty card list) but you can easily get away with less if you just play buff cards to empower your tokens or you play tutor, filter and recursion to ensure you have access to the few you do have
With the London Mulligan rule, you can often toss back a land or expensive spell and still come out swinging
With it, you can do damage and search your deck for a Basic Energy to attach to Cyclizar ex
We could spend an entire list explaining just what makes a good card
With the inclusion of newer cards such as Forest of Vitality (MEG 117) and Meganium (MEG 10) , the deck becomes significantly faster to set up, allowing you to play aggressively and prevent your opponent from setting up