Not only does the Instant remove any kind of permanent in play, but it also tucks the card back into their library
Modern isnt that fast right now, but there could be a future where your deck plans on comboing off after leading a turn on a cantrip where Serum Visions being slower matters
Some view it as a powerful finisher, while others only see it as a "win-more" card, effective when you're already ahead
The goal is to deal damage to Kartana and/or Pheromosa, then clean up with Buzzwole ex
Thats a huge amount of ramp for such little costs, provided you can keep her on the board
The potential of this card, for that reason, feels insane