A 2 mana rock means you have four mana on turn 3 to cast your commander (assuming you have a land), and 7, 11, and 21 power means it only takes three, two, or one attacks respectively with your commander to kill someone
As the permanent isnt entering the battlefield, it is just changing states
For instance, Maelstrom Pulse used to be a nice catch-all card for Jund midrange in Modern, cleaning up Lingering Souls tokens in one go
It functions as a combo deck with a reanimator engine
However, with limited numbers of essential cards like 004-018-mirabel-madrigal-gift-of-the-family and 004-013-julieta-madrigal-excellent-cook, the deck really isnt a strong choice in terms of overall power
Likewise, how legendary creatures like Emiel the Blessed or Tinybones, Trinket Thief became fabled figures in the game for one reason or another