Say goodbye to cluttered collections
You still cast these cards even if you do not pay the mana value on the card (if there is one), which means the cascade mechanic still fires off
Steel Overseer can grow all of our artifact creatures, like Sharding Sphinx, Myr Battlesphere, and Kappa Cannoneer
What are the weaknesses and retreat cost of this Veluza card
Sure, Ashiok can dominate the game and be an effective turn 3 kill if landed on an empty board early enough, but unlikely other Planeswalkers, it can also be quite effective played on the late game hammer, where not even Spell Pierce can answer it
But as a payoff for the discard deck, I think this Belle is pretty good