For example, Spire of Industry says ", Pay 1 life: Add one mana of any color
In the first case, the more reliable cards to add would be Fire The Cannons, Ba-Boom, Tritons Decree and Let the Storm rage on
Wistfulness, Vibrance, Emptiness, Deceit, and Catharsis change what they do based on the colors you use to cast them, which makes every decision feel meaningful
Gold is the more abundant currency, and will generally be earned by completing daily and weekly quests and filling out the battle pass (of which there is a free and premium version)
Since then, Path to Exile mostly disappeared from every Modern deck and was replaced either by Prismatic Ending or our #1 placed card
Villainous Wealth and Torment of Hailfire are good wincons once you have enough lands in play