The card in question is the Surge Foil Henneth Annun version of Reflecting Pool, a land that lets you create mana of any MTG color you could produce with your existing MTG lands
In fact, hes quick to point out that not only is Lignify his first card, its also one that he still plays to this day, in his Tuvasa the Sunlit Enchantress deck
Its unlikely youll ever want to risk attacking with Rallier, but the fact that you have the option is great
When its good, its great, but some games itll fail to do much
In a worst case scenario, Sphinx of the Revelation can still trigger itself
So if you can manage a 58% win%, which is possible even if heavily Rare-drafting, then the two types are equivalent in terms of the number of gems you spend to "buy" each pack