Games are better when they dont exceed two hours, and this strategy can risk hitting that point
If that creature dies, Zenos transforms into Shinryu, Transcendent Rivala massive flying dragon with a scary alternate win condition
You're playing mono-red, and normally your best card against mono-white is Outpost Siege
While Klomparens stated the ban was not intended to make Oops unplayable, cutting their valid win conditions by half is a fairly unambiguous move to push the deck back to novelty status
Outside of Black & White, several of the most valuable Unovan Pokemon appear in the Sun & Moon era, thanks in part to the ever-growing popularity of sets like Team Up and Unbroken Bonds
As such it is an incredibly efficient spell with a lot of raw countering power for the mana