The cost reduction gives you free equips on lots of strong equipment like the Mirrodin Swords, Umezawa's Jitte, and so on
And there are multiple steps, crucial for making sure you can access all your favorite Lorcana cards
White decks are known for generating tons of creature tokens, often going wide with Aggro and Lifegain effects
This means you can build around getting a full Party, as intended, or specialize in one of the four
Every time you discard a card, you get to choose a new benefit: You draw a card, make a Treasure, or drain your opponents
Then the enchantment also costs three, and this time the ETB is for dorks with a cheap three mana cost instead of smaller powers, which are typically the same stuff, and then you draw without mana, but again, just once per turn like the Vampire