Granted, Bitter Triumph is card parity, while this is card disadvantage, and haste is a big part of what puts Bitter Reunion over, but making Treasures is a way for Reanimator decks to hard-cast their big creatures and is just a generally powerful thing to do
Beyond that, the Pauper format specifically limits players to Common rarity cards, so it's the most budget-friendly way to explore with competitive play
Many Commander players run tri lands because, in a format where you can play a bunch of different colors, you want every possible way to fix your mana
Designer Notes: Put permanent cards in your graveyard to power up you commander and swarm the board with fungus tokens
A counterspell for noncreatures at two mana that also prevents your opponents from casting noncreature spells for the rest of the turn feels pretty powerful, even though its not without its limitations