It might have enough Servo/artifact synergy to see play, but its probably fringe
The event is listed as beginning October 29 (the game's global release date) and running until January 29
Flicker effects are also pretty interesting with battles
The -3 lets you destroy a target creature, and finally, the -6 gives you an emblem that states "whenever you gain life, target opponent loses that much life." Given that this card only costs four mana to cas t, it, like most of Witherbloom, is quite finely balanced and should see plenty of play across Standard and Commander
Next, Seismitoad is in third place with its cool pastel abstract art, followed by another epic thunderstorm-engulfed Zekrom ex full art card, and finally Kyurem ex amongst the ice caverns