Basically it gives flashback to the top card of your graveyard for an investment of three mana each time
In a dedicated deck trying to go wide with Soul Sisters effects, meeting Haliyas draw requirement, especially when casting her for the Warp cost, is rather easy
Their spoiler pages default to showing cards in the order they were revealed (handy for spoiler seasons that follow a story, like War of the Spark last spring)
3 Xolatoyac, The Smiling Flood Cataclysmic Death, With Dimples Never trust a tiny-armed axolotl god that smiles as it plunges your city underwater
But in common, +3/+3 was a little too much
There are successful land deck builds across Legacy that dont care about discarding an Arclight Phoenix or a land that can be recovered with Life from the Loam, or even a dredge card