This effect also exists on Arena, but Cliffs taps for mana, which is the difference between unplayable and incredibly useful
Fiendish Duo is a 6-mana big creature with first strike that doubles the damage any of your sources would do to an opponent
In a game where people are dropping 6/6 dragons or Earthbending 5/5 lands, a 1/1 fish is a negligible price to pay for unconditional, one-mana removal
Its more likely your creature will get trample and no stat bonuses
Lastly, from the Universes Beyond: Dungeons & Dragons Secret Lair, you can run Xenk, Paladin UnbrokenXenk, Paladin Unbroken as yet another functional Ethereal ArmorEthereal Armor
Destroying three lands and having a big creature in play is a way to get ahead, and you can turn excess lands into beaters, too