The Contraption deck isn't a permanent, and to the best of our knowledge it isn't a player eitheralthough, we've seen stranger things happen
While Moat isnt always the most powerful card, there are plenty of flying creatures in Magic, you can shut down plenty of creature-based decks
Control Win Condition creates an annoying bit of record-keeping that you want to obscure from your opponent (encouraging you to spend additional mental energy obscuring your busywork)
Unlike most cards, where you are limited to only four copies per deck, with Persistent Petitioners, you can have as many as you want
Most importantly, it's pretty slow, costing two to cast and two more to equip, and not doing anything until you start dealing damage and generating charge counters
If it was a permanent spell, such as an enchantment, creature, or artifact, they receive their promised gift after the permanent enters the battlefield