Not only will your tokens be able to counter spells, but if they successfully do so, you get to create more tokens
That said, we already have a pretty powerful black discard deck in Standard, with cards like Liliana of the Veil and Bandit's Talent
(They're artifacts with ", Sacrifice this token: Add one mana of any color.") Bottle-Cap Blast deals 5 damage to any target
Rowan makes cards that are already extremely strong such as Ad Nauseam and Bolas's Citadel EVEN STRONGER by making each drop of blood you pour into them discount your eventual game-winning spells, or even value pieces or tutors you might play along the way to secure your winning lines
Yuriko encourages you to play powerful and expensive finishers that turn her into a Heartless HidetsuguHeartless Hidetsugu of sorts and gives you reasons to play on-type creatures that may otherwise be pretty clunky, like Higure, the Still WindHigure, the Still Wind, Silent-Blade Oni, and Ink-Eyes
The mere fact that the Praetors, arguably the most terrifying creatures on New Phyrexia, are continuously bickering like bratty siblings