This is partially because of how powerful it is, but also partially because Wizards cant print better card draw than this
First and foremost, there's the card I found with the longest oracle text: Dance of the Dead
(You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.) As long as this card is in your graveyard, if you would learn, you may instead return this card to the battlefield
Well, mana spells are half the equation of a Storm deck, with the other half being card draw, which our commander transforms burn spells into
It can also be useful in Commander to clear a full stack since you can choose different targets for each copy, potentially letting you stop multiple players
Spike Feeder still has to pay a counter to generate each new Heliod trigger, like Ballista, but unlike ol Walky B, theres no inherent way to convert that loop into victory