While white has other token generators that are also sagas, particularly in current Standard, the sequence of token batches over multiple turns uniquely captures the progressive nature of the summon's animation, rather than creating them all at once
Illustrated by Mila Pesic Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Sartor Standard Legal Alchemy Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Looking through Gatherer for all of the cards that have scry, it's clear that if you were able to get both of these out, a deck with a heavy scry strategy (scrytegy?) could draw a ridiculous number of cards
You get to choose between a target-limited Quench, a Shock, or a non-flashbacking Faithless Looting for 2 mana
Keeping your opponents lands tapped the turn they come in keeps YOU a turn ahead, and slows down your opponents