It might be due to the very mixed colors the decks represent (in the past they have been balanced in some way to represent all colors equally)
With Saskia out, your Soldiers become even more efficient, dealing damage across two different players, giving you the potential to take out two players at once
Precons in the same release as MH3 left people questioning why, but the answer was overwhelmingly: because these decks are cool
Watermark: Selesnya Illustrated by Raymond Swanland Standard Not Legal Alchemy Not Legal Pioneer Legal Historic Not Legal Modern Legal Brawl Not Legal Legacy Legal Comp
You can also leverage this effect alongside Avacyn, Angel of Hope or Teferi's Protection to walk away unscathed as you raze your opponents
However, the main attraction is its effect, which lets you gain control of a creature until the end of the turn