Allowing you to get value from them as a commander on the turn you play them, and it can one-shot people if you have Wound Reflection, Archfiend of Despair, or Astarion, the Decadent in play since those abilities check the life loss as they resolve
Creature sac outlets and artifact sac outlets love the sacrifice fodder that token generators give them
And if all of this is still not enough to sell you on Selvala's raw power level, it is also worth noting that she is far more flexible than many of the other Green Commanders on this list: Unlike Marwyn, she does not automatically lock you into Elves
I prefer an organic end to the game, one that involves the natural outcome based on play of the game and interaction between players
From personal experience, they seem to sell out of top-tier tournament playables quite often
i would have to agree that we have too many pieces doing the same thing