Like most Magic: The Gathering cards, the value of Cat depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Bloomburrow Commander Tokens)
But any time a particular card starts fetching crazy money, it causes the issues for the TCG to only get worse
She could be the only creature or one of the only creatures in some Mono-Black Control deck but shes significantly worse at controlling the board than Wurmcoil Engine Grave Titan or Carnifex Demon
Like many other mechanics like threshold or metalcraft, these cards excel when you have max speed
While this strategy is considerably faster due to using less mana, it is worth noting that youll be very obviously telegraphing this move once youre setup, so youll need to be prepared for the table to play around it