>>28238124>I don't even know why Shaymin is this importantBy itself it is insanely strong. Drawing up to 6 cards from your deck is a great effect. For instance, this card was played when it was released during the Black and White era. It's Shaymin, but as a supporter card. It was never the preferred method of drawing, but decks would run them in low counts to supplement Juniper. Being a supporter, it's much, much weaker than Shaymin is.
Now think about the synergies that Shaymin has within the current meta. Ultra Ball was already a staple of decks before Shaymin - decks would rarely run less than 3. But add Shaymin into the mix, and Ultra Ball becomes so much more than what it currently is. It adds an insane amount of versatility to the card, allowing you to search for a pokemon or draw up to 6 cards. Now you have decks running 4 Ultra Ball nearly all the time because they've become incredible consistency cards. I don't think any player could count the number of times they would have had a dead hand if it had not been for an Ultra Ball. The end result is much faster decks with much higher consistency, which is the goal of 99% of decks (go fuck yourself wailord).