For 1 extra mana, Hylda turns your Impede Momentum into a 4/4 Elemental, or lets you really dig through your deck for the next stun counter card
For just one green, one white, and one blue mana, you could web-sling in anything from a Progenitus to a Jodah to an Atraxa
Taking a quick look at the ban list will reveal a format afraid of overpowered Eldrazi, a poorly designed Vehicle, and a creature that has an ability that control mages would die for on a spell
As if that wasnt good enough, once defeated, this Battle can be recast as Zilortha, Apex of Ikoria who is quite the threat
All these factors combined result in a cards total value and how much players are willing to buy and sell it for
Also, try lowering the price or reaching out to other MTG collectors.